{"id":305786,"date":"2024-01-12T19:44:18","date_gmt":"2024-01-12T12:44:18","guid":{"rendered":"https:\/\/hoanghamobile.com\/tin-tuc\/?p=305786"},"modified":"2026-11-05T14:05:08","modified_gmt":"2026-11-05T07:05:08","slug":"dien-tich-hinh-cau","status":"publish","type":"post","link":"https:\/\/hoanghamobile.com\/tin-tuc\/dien-tich-hinh-cau\/","title":{"rendered":"Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u: C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u v\u00e0 b\u00e0i t\u1eadp c\u00f3 l\u1eddi gi\u1ea3i"},"content":{"rendered":"<p><strong>Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u) b\u1eb1ng 4 l\u1ea7n di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n l\u1edbn: S = 4\u03c0R\u00b2, ho\u1eb7c S = \u03c0d\u00b2 n\u1ebfu bi\u1ebft \u0111\u01b0\u1eddng k\u00ednh d.<\/strong> V\u00ed d\u1ee5 h\u00ecnh c\u1ea7u b\u00e1n k\u00ednh 5 cm c\u00f3 di\u1ec7n t\u00edch S = 4 \u00d7 3,14 \u00d7 5\u00b2 = 314 cm\u00b2. B\u00e0i vi\u1ebft gi\u1ea3i th\u00edch h\u00ecnh c\u1ea7u, m\u1eb7t c\u1ea7u l\u00e0 g\u00ec, c\u00e1c c\u00f4ng th\u1ee9c di\u1ec7n t\u00edch, c\u00e1ch suy ng\u01b0\u1ee3c b\u00e1n k\u00ednh t\u1eeb di\u1ec7n t\u00edch, k\u00e8m b\u00e0i t\u1eadp c\u00f3 l\u1eddi gi\u1ea3i.<\/p>\n<p><strong>T\u00f3m t\u1eaft nhanh:<\/strong><\/p>\n<ul>\n<li><strong>Bi\u1ebft b\u00e1n k\u00ednh R:<\/strong> S = 4\u03c0R\u00b2.<\/li>\n<li><strong>Bi\u1ebft \u0111\u01b0\u1eddng k\u00ednh d:<\/strong> S = \u03c0d\u00b2 (v\u00ec R = d\/2).<\/li>\n<li><strong>Bi\u1ebft di\u1ec7n t\u00edch, t\u00ecm b\u00e1n k\u00ednh:<\/strong> R = \u221a(S \/ 4\u03c0).<\/li>\n<li><strong>Th\u1ec3 t\u00edch kh\u1ed1i c\u1ea7u (\u0111\u1ec3 ph\u00e2n bi\u1ec7t):<\/strong> V = 4\/3\u00b7\u03c0R\u00b3, \u0111\u01a1n v\u1ecb kh\u1ed1i (cm\u00b3, m\u00b3).<\/li>\n<\/ul>\n<p><img fetchpriority=\"high\" decoding=\"async\" class=\"aligncenter wp-image-305799 size-full\" src=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-1.jpg\" alt=\"Ph\u00e2n bi\u1ec7t h\u00ecnh tr\u00f2n v\u00e0 h\u00ecnh c\u1ea7u\" width=\"800\" height=\"450\" srcset=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-1.jpg 800w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-1-300x169.jpg 300w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-1-768x432.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/p>\n<h2>H\u00ecnh c\u1ea7u, m\u1eb7t c\u1ea7u l\u00e0 g\u00ec?<\/h2>\n<p><strong>M\u1eb7t c\u1ea7u<\/strong> t\u00e2m O, b\u00e1n k\u00ednh R l\u00e0 t\u1eadp h\u1ee3p t\u1ea5t c\u1ea3 c\u00e1c \u0111i\u1ec3m trong kh\u00f4ng gian c\u00e1ch \u0111i\u1ec3m O m\u1ed9t kho\u1ea3ng b\u1eb1ng R. <strong>H\u00ecnh c\u1ea7u (kh\u1ed1i c\u1ea7u)<\/strong> g\u1ed3m m\u1eb7t c\u1ea7u v\u00e0 to\u00e0n b\u1ed9 ph\u1ea7n kh\u00f4ng gian b\u00ean trong n\u00f3. Khi quay m\u1ed9t n\u1eeda h\u00ecnh tr\u00f2n quanh \u0111\u01b0\u1eddng k\u00ednh c\u1ee7a n\u00f3 m\u1ed9t v\u00f2ng, ta \u0111\u01b0\u1ee3c m\u1ed9t h\u00ecnh c\u1ea7u.<\/p>\n<ul>\n<li>\u0110o\u1ea1n n\u1ed1i t\u00e2m v\u1edbi m\u1ed9t \u0111i\u1ec3m tr\u00ean m\u1eb7t c\u1ea7u l\u00e0 b\u00e1n k\u00ednh R; \u0111\u01b0\u1eddng k\u00ednh d = 2R.<\/li>\n<li>M\u1eb7t ph\u1eb3ng \u0111i qua t\u00e2m c\u1eaft h\u00ecnh c\u1ea7u theo m\u1ed9t <strong>h\u00ecnh tr\u00f2n l\u1edbn<\/strong> c\u00f3 b\u00e1n k\u00ednh b\u1eb1ng R.<\/li>\n<li>M\u1ecdi \u0111\u01b0\u1eddng th\u1eb3ng \u0111i qua t\u00e2m \u0111\u1ec1u l\u00e0 tr\u1ee5c \u0111\u1ed1i x\u1ee9ng c\u1ee7a h\u00ecnh c\u1ea7u.<\/li>\n<\/ul>\n<p>V\u00ec v\u1eady khi n\u00f3i &#8220;di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u&#8221;, ng\u01b0\u1eddi ta th\u01b0\u1eddng hi\u1ec3u l\u00e0 di\u1ec7n t\u00edch c\u1ee7a m\u1eb7t c\u1ea7u bao quanh h\u00ecnh c\u1ea7u.<\/p>\n<h2>C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (m\u1eb7t c\u1ea7u)<\/h2>\n<p style=\"text-align: center;\"><strong>S = 4\u03c0R\u00b2 = \u03c0d\u00b2<\/strong><\/p>\n<ul>\n<li>S: di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u (cm\u00b2, m\u00b2\u2026).<\/li>\n<li>R: b\u00e1n k\u00ednh; d: \u0111\u01b0\u1eddng k\u00ednh (d = 2R).<\/li>\n<li>\u03c0 \u2248 3,14.<\/li>\n<\/ul>\n<p>Di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n l\u1edbn l\u00e0 \u03c0R\u00b2, n\u00ean di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u \u0111\u00fang b\u1eb1ng 4 l\u1ea7n di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n l\u1edbn. C\u00e1ch t\u00ednh di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n c\u00f3 trong b\u00e0i <a href=\"https:\/\/hoanghamobile.com\/tin-tuc\/dien-tich-hinh-tron\/\">di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n<\/a>.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter wp-image-305802 size-full\" src=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-4.jpg\" alt=\"C\u00f4ng th\u1ee9c di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u S = 4\u03c0R\u00b2\" width=\"800\" height=\"450\" srcset=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-4.jpg 800w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-4-300x169.jpg 300w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-4-768x432.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/p>\n<p>Trong nhi\u1ec1u t\u00e0i li\u1ec7u, di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u c\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 &#8220;di\u1ec7n t\u00edch xung quanh h\u00ecnh c\u1ea7u&#8221; (S<sub>xq<\/sub> = 4\u03c0R\u00b2). H\u00ecnh c\u1ea7u kh\u00f4ng c\u00f3 m\u1eb7t \u0111\u00e1y n\u00ean di\u1ec7n t\u00edch xung quanh v\u00e0 di\u1ec7n t\u00edch to\u00e0n ph\u1ea7n l\u00e0 m\u1ed9t.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter wp-image-305803 size-full\" src=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-5.jpg\" alt=\"Di\u1ec7n t\u00edch xung quanh h\u00ecnh c\u1ea7u Sxq = 4\u03c0r\u00b2\" width=\"800\" height=\"450\" srcset=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-5.jpg 800w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-5-300x169.jpg 300w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-5-768x432.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/p>\n<h2>C\u00e1ch t\u00ednh di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u theo t\u1eebng d\u1eef ki\u1ec7n<\/h2>\n<table>\n<thead>\n<tr>\n<th>\u0110\u1ec1 cho<\/th>\n<th>C\u00e1ch l\u00e0m<\/th>\n<th>V\u00ed d\u1ee5<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>B\u00e1n k\u00ednh R<\/td>\n<td>S = 4\u03c0R\u00b2<\/td>\n<td>R = 9 m \u2192 S = 324\u03c0 \u2248 1 017,36 m\u00b2<\/td>\n<\/tr>\n<tr>\n<td>\u0110\u01b0\u1eddng k\u00ednh d<\/td>\n<td>S = \u03c0d\u00b2 (ho\u1eb7c R = d\/2 r\u1ed3i 4\u03c0R\u00b2)<\/td>\n<td>d = 4 cm \u2192 S = 16\u03c0 cm\u00b2<\/td>\n<\/tr>\n<tr>\n<td>Th\u1ec3 t\u00edch V<\/td>\n<td>T\u00ecm R = \u221b(3V \/ 4\u03c0) r\u1ed3i S = 4\u03c0R\u00b2<\/td>\n<td>V = 36\u03c0 cm\u00b3 \u2192 R = 3 cm \u2192 S = 36\u03c0 cm\u00b2<\/td>\n<\/tr>\n<tr>\n<td>Di\u1ec7n t\u00edch, c\u1ea7n t\u00ecm R<\/td>\n<td>R = \u221a(S \/ 4\u03c0)<\/td>\n<td>S = 144\u03c0 cm\u00b2 \u2192 R = 6 cm<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-305808 size-full\" src=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-.jpg\" alt=\"C\u00f4ng th\u1ee9c S = 4\u03c0R\u00b2\" width=\"800\" height=\"450\" srcset=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-.jpg 800w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau--300x169.jpg 300w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau--768x432.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/p>\n<h2>Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u v\u00e0 th\u1ec3 t\u00edch kh\u1ed1i c\u1ea7u kh\u00e1c nhau th\u1ebf n\u00e0o?<\/h2>\n<table>\n<thead>\n<tr>\n<th>\u0110\u1ea1i l\u01b0\u1ee3ng<\/th>\n<th>C\u00f4ng th\u1ee9c<\/th>\n<th>\u0110\u01a1n v\u1ecb<\/th>\n<th>Khi R t\u0103ng g\u1ea5p \u0111\u00f4i<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u<\/td>\n<td>S = 4\u03c0R\u00b2<\/td>\n<td>cm\u00b2, m\u00b2<\/td>\n<td>T\u0103ng 4 l\u1ea7n<\/td>\n<\/tr>\n<tr>\n<td>Th\u1ec3 t\u00edch kh\u1ed1i c\u1ea7u<\/td>\n<td>V = 4\/3\u00b7\u03c0R\u00b3 = \u03c0d\u00b3\/6<\/td>\n<td>cm\u00b3, m\u00b3<\/td>\n<td>T\u0103ng 8 l\u1ea7n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>H\u01b0\u1edbng d\u1eabn chi ti\u1ebft v\u1ec1 th\u1ec3 t\u00edch c\u00f3 trong b\u00e0i <a href=\"https:\/\/hoanghamobile.com\/tin-tuc\/the-tich-hinh-cau\/\">th\u1ec3 t\u00edch h\u00ecnh c\u1ea7u<\/a>.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-305804 size-full\" src=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-6.jpg\" alt=\"C\u00f4ng th\u1ee9c th\u1ec3 t\u00edch kh\u1ed1i c\u1ea7u V = 4\/3\u03c0R\u00b3\" width=\"800\" height=\"450\" srcset=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-6.jpg 800w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-6-300x169.jpg 300w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-6-768x432.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-305807 size-full\" src=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-9.jpg\" alt=\"Th\u1ec3 t\u00edch kh\u1ed1i c\u1ea7u theo b\u00e1n k\u00ednh v\u00e0 \u0111\u01b0\u1eddng k\u00ednh\" width=\"800\" height=\"450\" srcset=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-9.jpg 800w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-9-300x169.jpg 300w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-9-768x432.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/p>\n<h2>B\u00e0i t\u1eadp di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u c\u00f3 l\u1eddi gi\u1ea3i<\/h2>\n<p><strong>B\u00e0i 1:<\/strong> T\u00ednh di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u c\u00f3 b\u00e1n k\u00ednh 9 m.<br \/>L\u1eddi gi\u1ea3i: S = 4 \u00d7 3,14 \u00d7 9\u00b2 = 4 \u00d7 3,14 \u00d7 81 = 1 017,36 m\u00b2.<\/p>\n<p><strong>B\u00e0i 2 (tr\u1eafc nghi\u1ec7m):<\/strong> H\u00ecnh c\u1ea7u c\u00f3 \u0111\u01b0\u1eddng k\u00ednh d = 4 cm th\u00ec di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u l\u00e0: A. 9\u03c0; B. 36\u03c0; C. 16\u03c0; D. 12\u03c0 (cm\u00b2).<br \/>L\u1eddi gi\u1ea3i: R = 4 : 2 = 2 cm, S = 4\u03c0 \u00d7 2\u00b2 = 16\u03c0 cm\u00b2. \u0110\u00e1p \u00e1n C.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-305806 size-full\" src=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-8.jpg\" alt=\"B\u00e0i t\u1eadp di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u \u0111\u01b0\u1eddng k\u00ednh 4 cm\" width=\"800\" height=\"450\" srcset=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-8.jpg 800w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-8-300x169.jpg 300w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-8-768x432.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/p>\n<p><strong>B\u00e0i 3:<\/strong> M\u1ed9t qu\u1ea3 b\u00f3ng c\u00f3 \u0111\u01b0\u1eddng k\u00ednh 22 cm. T\u00ednh di\u1ec7n t\u00edch b\u1ec1 m\u1eb7t qu\u1ea3 b\u00f3ng.<br \/>L\u1eddi gi\u1ea3i: S = \u03c0d\u00b2 = 3,14 \u00d7 22\u00b2 = 3,14 \u00d7 484 = 1 519,76 cm\u00b2.<\/p>\n<p><strong>B\u00e0i 4:<\/strong> M\u1eb7t c\u1ea7u c\u00f3 di\u1ec7n t\u00edch 144\u03c0 cm\u00b2. T\u00ednh b\u00e1n k\u00ednh.<br \/>L\u1eddi gi\u1ea3i: 4\u03c0R\u00b2 = 144\u03c0 \u21d2 R\u00b2 = 36 \u21d2 R = 6 cm.<\/p>\n<p><strong>B\u00e0i 5 (n\u1eeda h\u00ecnh c\u1ea7u):<\/strong> T\u00ednh di\u1ec7n t\u00edch to\u00e0n ph\u1ea7n c\u1ee7a n\u1eeda h\u00ecnh c\u1ea7u b\u00e1n k\u00ednh 3 cm (g\u1ed3m m\u1eb7t cong v\u00e0 m\u1eb7t ph\u1eb3ng h\u00ecnh tr\u00f2n).<br \/>L\u1eddi gi\u1ea3i: m\u1eb7t cong = 2\u03c0R\u00b2 = 18\u03c0; m\u1eb7t \u0111\u00e1y = \u03c0R\u00b2 = 9\u03c0; t\u1ed5ng 27\u03c0 \u2248 84,78 cm\u00b2.<\/p>\n<p><strong>B\u00e0i 6:<\/strong> N\u1ebfu b\u00e1n k\u00ednh h\u00ecnh c\u1ea7u t\u0103ng g\u1ea5p \u0111\u00f4i th\u00ec di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u thay \u0111\u1ed5i th\u1ebf n\u00e0o?<br \/>L\u1eddi gi\u1ea3i: S&#8217; = 4\u03c0(2R)\u00b2 = 4 \u00d7 4\u03c0R\u00b2 = 4S, t\u1ee9c di\u1ec7n t\u00edch t\u0103ng 4 l\u1ea7n.<\/p>\n<h2>L\u01b0u \u00fd khi t\u00ednh di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u<\/h2>\n<ul>\n<li>\u0110\u1ec1 cho \u0111\u01b0\u1eddng k\u00ednh th\u00ec nh\u1edb chia \u0111\u00f4i tr\u01b0\u1edbc khi d\u00f9ng 4\u03c0R\u00b2, ho\u1eb7c d\u00f9ng lu\u00f4n \u03c0d\u00b2.<\/li>\n<li>Di\u1ec7n t\u00edch ghi \u0111\u01a1n v\u1ecb vu\u00f4ng (cm\u00b2, m\u00b2), th\u1ec3 t\u00edch ghi \u0111\u01a1n v\u1ecb kh\u1ed1i (cm\u00b3, m\u00b3).<\/li>\n<li>N\u1ebfu \u0111\u1ec1 y\u00eau c\u1ea7u &#8220;\u0111\u1ec3 k\u1ebft qu\u1ea3 theo \u03c0&#8221; th\u00ec kh\u00f4ng thay \u03c0 = 3,14.<\/li>\n<li>\u0110\u1eebng nh\u1ea7m h\u00ecnh c\u1ea7u v\u1edbi h\u00ecnh tr\u00f2n: h\u00ecnh tr\u00f2n l\u00e0 h\u00ecnh ph\u1eb3ng, di\u1ec7n t\u00edch \u03c0R\u00b2; h\u00ecnh c\u1ea7u l\u00e0 h\u00ecnh kh\u00f4ng gian.<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-305801 size-full\" src=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-3.jpg\" alt=\"H\u00ecnh c\u1ea7u v\u00e0 c\u00e1c h\u00ecnh kh\u1ed1i trong kh\u00f4ng gian\" width=\"800\" height=\"450\" srcset=\"https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-3.jpg 800w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-3-300x169.jpg 300w, https:\/\/hoanghamobile.com\/tin-tuc\/wp-content\/uploads\/2024\/01\/dien-tich-hinh-cau-3-768x432.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/p>\n<h2>C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p<\/h2>\n<h3>C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u l\u00e0 g\u00ec?<\/h3>\n<p>Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (m\u1eb7t c\u1ea7u) l\u00e0 S = 4\u03c0R\u00b2, v\u1edbi R l\u00e0 b\u00e1n k\u00ednh; n\u1ebfu bi\u1ebft \u0111\u01b0\u1eddng k\u00ednh d th\u00ec S = \u03c0d\u00b2.<\/p>\n<h3>Di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u v\u00e0 di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u c\u00f3 gi\u1ed1ng nhau kh\u00f4ng?<\/h3>\n<p>C\u00f3. Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u trong c\u00e1c b\u00e0i to\u00e1n ch\u00ednh l\u00e0 di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u bao quanh h\u00ecnh c\u1ea7u, t\u00ednh b\u1eb1ng 4\u03c0R\u00b2.<\/p>\n<h3>Di\u1ec7n t\u00edch xung quanh h\u00ecnh c\u1ea7u t\u00ednh th\u1ebf n\u00e0o?<\/h3>\n<p>Di\u1ec7n t\u00edch xung quanh h\u00ecnh c\u1ea7u c\u0169ng l\u00e0 S<sub>xq<\/sub> = 4\u03c0R\u00b2, v\u00ec h\u00ecnh c\u1ea7u kh\u00f4ng c\u00f3 m\u1eb7t \u0111\u00e1y.<\/p>\n<h3>V\u00ec sao di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u b\u1eb1ng 4 l\u1ea7n di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n l\u1edbn?<\/h3>\n<p>H\u00ecnh tr\u00f2n l\u1edbn c\u00f3 di\u1ec7n t\u00edch \u03c0R\u00b2, c\u00f2n m\u1eb7t c\u1ea7u c\u00f3 di\u1ec7n t\u00edch 4\u03c0R\u00b2, n\u00ean m\u1eb7t c\u1ea7u \u0111\u00fang b\u1eb1ng 4 l\u1ea7n h\u00ecnh tr\u00f2n l\u1edbn. \u0110\u00e2y l\u00e0 k\u1ebft qu\u1ea3 ch\u1ee9ng minh \u0111\u01b0\u1ee3c b\u1eb1ng t\u00edch ph\u00e2n, Archimedes \u0111\u00e3 ph\u00e1t hi\u1ec7n t\u1eeb th\u1eddi c\u1ed5 \u0111\u1ea1i.<\/p>\n<h3>Bi\u1ebft di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u, t\u00ecm b\u00e1n k\u00ednh th\u1ebf n\u00e0o?<\/h3>\n<p>L\u1ea5y di\u1ec7n t\u00edch chia cho 4\u03c0 r\u1ed3i khai c\u0103n: R = \u221a(S \/ 4\u03c0). V\u00ed d\u1ee5 S = 144\u03c0 cm\u00b2 th\u00ec R = 6 cm.<\/p>\n<h3>Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u h\u1ecdc \u1edf l\u1edbp m\u1ea5y?<\/h3>\n<p>Di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u v\u00e0 th\u1ec3 t\u00edch h\u00ecnh c\u1ea7u \u0111\u01b0\u1ee3c h\u1ecdc trong ch\u01b0\u01a1ng h\u00ecnh h\u1ecdc kh\u00f4ng gian c\u1ee7a To\u00e1n l\u1edbp 9, v\u00e0 d\u00f9ng l\u1ea1i \u1edf ch\u01b0\u01a1ng m\u1eb7t c\u1ea7u To\u00e1n l\u1edbp 12.<\/p>\n<p><script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"FAQPage\",\n  \"mainEntity\": [\n    {\n      \"@type\": \"Question\",\n      \"name\": \"C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u l\u00e0 g\u00ec?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (m\u1eb7t c\u1ea7u) l\u00e0 S = 4\u03c0R\u00b2, v\u1edbi R l\u00e0 b\u00e1n k\u00ednh; n\u1ebfu bi\u1ebft \u0111\u01b0\u1eddng k\u00ednh d th\u00ec S = \u03c0d\u00b2.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u v\u00e0 di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u c\u00f3 gi\u1ed1ng nhau kh\u00f4ng?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"C\u00f3. Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u trong c\u00e1c b\u00e0i to\u00e1n ch\u00ednh l\u00e0 di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u bao quanh h\u00ecnh c\u1ea7u, t\u00ednh b\u1eb1ng 4\u03c0R\u00b2.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Di\u1ec7n t\u00edch xung quanh h\u00ecnh c\u1ea7u t\u00ednh th\u1ebf n\u00e0o?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Di\u1ec7n t\u00edch xung quanh h\u00ecnh c\u1ea7u c\u0169ng l\u00e0 Sxq = 4\u03c0R\u00b2, v\u00ec h\u00ecnh c\u1ea7u kh\u00f4ng c\u00f3 m\u1eb7t \u0111\u00e1y.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"V\u00ec sao di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u b\u1eb1ng 4 l\u1ea7n di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n l\u1edbn?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"H\u00ecnh tr\u00f2n l\u1edbn c\u00f3 di\u1ec7n t\u00edch \u03c0R\u00b2, c\u00f2n m\u1eb7t c\u1ea7u c\u00f3 di\u1ec7n t\u00edch 4\u03c0R\u00b2, n\u00ean m\u1eb7t c\u1ea7u \u0111\u00fang b\u1eb1ng 4 l\u1ea7n h\u00ecnh tr\u00f2n l\u1edbn. \u0110\u00e2y l\u00e0 k\u1ebft qu\u1ea3 ch\u1ee9ng minh \u0111\u01b0\u1ee3c b\u1eb1ng t\u00edch ph\u00e2n, Archimedes \u0111\u00e3 ph\u00e1t hi\u1ec7n t\u1eeb th\u1eddi c\u1ed5 \u0111\u1ea1i.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Bi\u1ebft di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u, t\u00ecm b\u00e1n k\u00ednh th\u1ebf n\u00e0o?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"L\u1ea5y di\u1ec7n t\u00edch chia cho 4\u03c0 r\u1ed3i khai c\u0103n: R = \u221a(S \/ 4\u03c0). V\u00ed d\u1ee5 S = 144\u03c0 cm\u00b2 th\u00ec R = 6 cm.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u h\u1ecdc \u1edf l\u1edbp m\u1ea5y?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u v\u00e0 th\u1ec3 t\u00edch h\u00ecnh c\u1ea7u \u0111\u01b0\u1ee3c h\u1ecdc trong ch\u01b0\u01a1ng h\u00ecnh h\u1ecdc kh\u00f4ng gian c\u1ee7a To\u00e1n l\u1edbp 9, v\u00e0 d\u00f9ng l\u1ea1i \u1edf ch\u01b0\u01a1ng m\u1eb7t c\u1ea7u To\u00e1n l\u1edbp 12.\"\n      }\n    }\n  ]\n}\n<\/script><\/p>\n<h2>K\u1ebft lu\u1eadn<\/h2>\n<p>Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u \u0111\u01b0\u1ee3c t\u00ednh b\u1eb1ng S = 4\u03c0R\u00b2 ho\u1eb7c \u03c0d\u00b2, b\u1eb1ng 4 l\u1ea7n di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n l\u1edbn. Ch\u1ec9 c\u1ea7n x\u00e1c \u0111\u1ecbnh \u0111\u00fang b\u00e1n k\u00ednh, \u0111\u1ed5i \u0111\u01b0\u1eddng k\u00ednh khi c\u1ea7n v\u00e0 ghi \u0111\u01a1n v\u1ecb vu\u00f4ng l\u00e0 gi\u1ea3i \u0111\u01b0\u1ee3c m\u1ecdi d\u1ea1ng b\u00e0i c\u01a1 b\u1ea3n. B\u1ea1n c\u00f3 th\u1ec3 tham kh\u1ea3o th\u00eam c\u00e1c b\u00e0i <a href=\"https:\/\/hoanghamobile.com\/tin-tuc\/cong-thuc-the-tich-khoi-tron-xoay\/\">th\u1ec3 t\u00edch kh\u1ed1i tr\u00f2n xoay<\/a> v\u00e0 <a href=\"https:\/\/hoanghamobile.com\/tin-tuc\/dien-tich-xung-quanh-hinh-tru\/\">di\u1ec7n t\u00edch xung quanh h\u00ecnh tr\u1ee5<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u) b\u1eb1ng 4 l\u1ea7n di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n l\u1edbn: S = 4\u03c0R\u00b2, ho\u1eb7c S = \u03c0d\u00b2 n\u1ebfu bi\u1ebft \u0111\u01b0\u1eddng k\u00ednh d. V\u00ed d\u1ee5 h\u00ecnh c\u1ea7u b\u00e1n k\u00ednh 5 cm c\u00f3 di\u1ec7n t\u00edch S = 4 \u00d7 3,14 \u00d7 5\u00b2 = 314 cm\u00b2. B\u00e0i vi\u1ebft gi\u1ea3i th\u00edch h\u00ecnh c\u1ea7u, [&hellip;]<\/p>\n","protected":false},"author":65,"featured_media":305787,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_yoast_wpseo_focuskw":"di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u","_yoast_wpseo_title":"C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (m\u1eb7t c\u1ea7u) v\u00e0 b\u00e0i t\u1eadp","_yoast_wpseo_metadesc":"Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (m\u1eb7t c\u1ea7u) S = 4\u03c0R\u00b2 = \u03c0d\u00b2. C\u00e1ch t\u00ednh theo b\u00e1n k\u00ednh, \u0111\u01b0\u1eddng k\u00ednh, t\u00ecm b\u00e1n k\u00ednh t\u1eeb di\u1ec7n t\u00edch, ph\u00e2n bi\u1ec7t v\u1edbi th\u1ec3 t\u00edch v\u00e0 b\u00e0i t\u1eadp c\u00f3 l\u1eddi gi\u1ea3i.","footnotes":""},"categories":[3910,30453],"tags":[],"class_list":["post-305786","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-kham-pha","category-kien-thuc"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.3 (Yoast SEO v27.4) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (m\u1eb7t c\u1ea7u) v\u00e0 b\u00e0i t\u1eadp<\/title>\n<meta name=\"description\" content=\"Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (m\u1eb7t c\u1ea7u) S = 4\u03c0R\u00b2 = \u03c0d\u00b2. C\u00e1ch t\u00ednh theo b\u00e1n k\u00ednh, \u0111\u01b0\u1eddng k\u00ednh, t\u00ecm b\u00e1n k\u00ednh t\u1eeb di\u1ec7n t\u00edch, ph\u00e2n bi\u1ec7t v\u1edbi th\u1ec3 t\u00edch v\u00e0 b\u00e0i t\u1eadp c\u00f3 l\u1eddi gi\u1ea3i.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/hoanghamobile.com\/tin-tuc\/dien-tich-hinh-cau\/\" \/>\n<meta property=\"og:locale\" content=\"vi_VN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u: C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch m\u1eb7t c\u1ea7u v\u00e0 b\u00e0i t\u1eadp c\u00f3 l\u1eddi gi\u1ea3i\" \/>\n<meta property=\"og:description\" content=\"Di\u1ec7n t\u00edch h\u00ecnh c\u1ea7u (m\u1eb7t c\u1ea7u) S = 4\u03c0R\u00b2 = \u03c0d\u00b2. 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