C\u00f4ng th\u1ee9c t\u00ednh chu vi h\u00ecnh tr\u00f2n hay di\u1ec7n t\u00edch l\u00e0 m\u1ed9t trong s\u1ed1 nh\u1eefng c\u00f4ng th\u1ee9c m\u00e0 b\u1ea5t k\u1ef3 ai d\u00f9 l\u00e0 h\u1ecdc sinh hay sinh vi\u00ean c\u0169ng c\u1ea7n n\u1eafm \u0111\u01b0\u1ee3c \u0111\u1ec3 \u1ee9ng d\u1ee5ng \u0111\u1ec3 l\u00e0m b\u00e0i t\u1eadp. N\u1ebfu nh\u01b0 c\u00e1c b\u1ea1n kh\u00f4ng n\u1eafm v\u1eefng \u0111\u01b0\u1ee3c nh\u1eefng h\u00ecnh c\u00f4ng th\u1ee9c n\u00e0y th\u00ec s\u1ebd kh\u00f4ng s\u1ebd l\u00e0m \u0111\u01b0\u1ee3c b\u00e0i t\u1eadp.<\/p>\n

C\u00f4ng th\u1ee9c t\u00ednh chu vi hay di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n l\u00e0 nh\u1eefng ki\u1ebfn th\u1ee9c c\u01a1 b\u1ea3n n\u1ec1n t\u1ea3ng n\u1ec1n t\u1ea3ng quan tr\u1ecdng \u0111\u1ec3 gi\u00fap c\u00e1c b\u1ea1n c\u00f3 th\u1ec3 t\u00ednh to\u00e1n m\u1ed9t c\u00e1ch \u0111o \u0111\u1ea1c ch\u00ednh x\u00e1c nh\u1ea5t v\u00e0 nhanh nh\u1ea5t.<\/p>\n

C\u00f4ng th\u1ee9c t\u00ednh chu vi h\u00ecnh tr\u00f2n nhanh nh\u1ea5t<\/h2>\n

Kh\u00e1i ni\u1ec7m: Cu vi h\u00ecnh tr\u00f2n hay l\u00e0 \u0111\u01b0\u1eddng tr\u00f2ng l\u00e0 \u0111\u01b0\u1eddng bi\u00ean gi\u1edbi h\u1ea1n c\u1ee7a h\u00ecnh tr\u00f2n. C\u00f4ng th\u1ee9c t\u00ednh chu vi h\u00ecnh tr\u00f2n \u0111\u01b0\u1ee3c t\u00ednh b\u1eb1ng l\u1ea5y \u0111\u01b0\u1eddng k\u00ednh nh\u00e2n v\u1edbi Pi hay 2 l\u1ea7n b\u00e1n k\u00ednh nh\u00e2n v\u1edbi Pi.<\/p>\n

<\/p>\n

C\u00f4ng th\u1ee9c t\u00ednh chu vi h\u00ecnh tr\u00f2n: C= D x Pi ho\u1eb7c C = (Rx2)xpi<\/p>\n

Trong \u0111\u00f3:<\/p>\n

C: l\u00e0 chu vi c\u1ee7a h\u00ecnh tr\u00f2n<\/p>\n

D l\u00e0 \u0111\u01b0\u1eddng k\u00ednh h\u00ecnh tr\u00f2n<\/p>\n

Pi: s\u1ed1 pi = 3,14<\/p>\n

R: B\u00e1n k\u00ednh c\u1ee7a h\u00ecnh tr\u00f2n.<\/p>\n

C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n v\u00e0 chu vi h\u00ecnh tr\u00f2n c\u00f3 th\u1ec3 \u00e1p d\u1ee5ng \u0111\u01b0\u1ee3c nhi\u1ec1u b\u00e0i to\u00e1n t\u1eeb c\u01a1 b\u1ea3n \u0111\u1ebfn n\u00e2ng cao. B\u00ean c\u1ea1nh \u0111\u00f3 c\u00f4ng th\u1ee9c n\u00e0y c\u00f2n c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng v\u00e0o c\u00e1c b\u00e0i to\u00e1n ph\u1ee9c t\u1ea1p kh\u00e1c v\u1edbi nhi\u1ec1u h\u00ecnh ph\u1ee9c t\u1ea1p kh\u00e1c. V\u00ed d\u1ee5\u00a0 nh\u01b0 t\u00ednh di\u1ec7n t\u00edch tam gi\u00e1c v\u00e0 di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n khi hai h\u00ecnh n\u00e0y giao nhau.<\/p>\n

B\u00e0i t\u1eadp \u00e1p d\u1ee5ng v\u1ec1 c\u00e1ch t\u00ednh chu vi h\u00ecnh tr\u00f2n<\/h3>\n

B\u00e0i t\u1eadp 1:<\/strong><\/p>\n

T\u00ednh chu vi h\u00ecnh tr\u00f2n c\u00f3 \u0111\u01b0\u1eddng k\u00ednh d:<\/p>\n

\n
1. a) d = 0,6cm; \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 b) d = 2,5dm; \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 c\u00a0m<\/li>\n<\/ol>\n

   Chu vi c\u1ee7a h\u00ecnh tr\u00f2n l\u00e0:<\/p>\n

   \n
   1. a) 0,6 x 3,14 = 1,884 (cm)<\/li>\n
   2. b) 2,5 x 3,14 = 7,85 (dm)<\/li>\n
   3. c)\u00a0m = 0,8m<\/li>\n<\/ol>\n

      0,8 x 3,14 = 2,512 m<\/p>\n

      \u0110\u00e1p s\u1ed1: a) 1,884cm; b) 7,85dm; c) 2,512m<\/p>\n

      B\u00e0i t\u1eadp 2:<\/strong><\/p>\n

      T\u00ednh chu vi h\u00ecnh tr\u00f2n c\u00f3 b\u00e1n k\u00ednh r:<\/p>\n

      \n
      1. a) r = 2,75cm; \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 b) r = 6,5dm; \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0c) r =\u00a01212m<\/li>\n<\/ol>\n

         B\u00e0i gi\u1ea3i:<\/p>\n

         Chu vi c\u1ee7a h\u00ecnh tr\u00f2n l\u00e0:<\/p>\n

         \n
         1. a) 2,75 x 2 x 3,14 = 17,27 (cm)<\/li>\n
         2. b) 6,5 x 2 x 3,14 = 40,82 (dm)<\/li>\n
         3. c)\u00a0\u00a01212m = 0,5m<\/li>\n<\/ol>\n

            0,5 x 2 x 3,14 = 3,14 (m)<\/p>\n

            \u0110\u00e1p s\u1ed1:<\/p>\n

            \n
            1. a) 17,27cm; b) 40,82dm; c)3,14mM\u1ed9t b\u00e1nh xe \u00f4 t\u00f4 c\u00f3 \u0111\u01b0\u1eddng k\u00ednh l\u00e0 0,75m. T\u00ednh chu vi c\u1ee7a b\u00e1nh xe \u0111\u00f3.<\/li>\n<\/ol>\n

               B\u00e0i t\u1eadp 3:<\/strong><\/p>\n

               B\u00e0i gi\u1ea3i:<\/p>\n

               Chu vi c\u1ee7a b\u00e1nh xe l\u00e0: 0,75 x 3,14 = 2,355m<\/p>\n

               \u0110\u00e1p s\u1ed1:\u00a02,355m.<\/p>\n

               B\u00e0i t\u1eadp 4:<\/strong><\/p>\n

               Cho h\u00ecnh tr\u00f2n t\u00e2m O c\u00f3 \u0111\u01b0\u1eddng k\u00ednh d\u00e0i 20cm. T\u00ednh di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n \u0111\u00f3<\/p>\n

               Di\u1ec7n t\u00edch h\u00ecnh tr\u00f2n t\u00e2m O: S =\u00a0r2\u00a0\/ 4 . 3,14 = 314 \u00a0(cm2)<\/p>\n

               Gi\u1ea3i:\u00a0<\/strong><\/p>\n

               Chu vi h\u00ecnh tr\u00f2n l\u00e0: C = d x 3,14 = 30 x 3,14 = 94,2(cm)<\/p>\n

               B\u00e0i t\u1eadp 5:<\/strong><\/p>\n

               Cho h\u00ecnh tr\u00f2n t\u00e2m O c\u00f3 b\u00e1n k\u00ednh r = 10cm. T\u00ednh chu vi h\u00ecnh tr\u00f2n \u0111\u00f3<\/p>\n

               Gi\u1ea3i:<\/strong><\/p>\n

               Chu vi c\u1ee7a h\u00ecnh tr\u00f2n t\u00e2m O l\u00e0: C = 2 x r x 3,14 = 62,8 (cm)<\/p>\n

               Tr\u00ean \u0111\u00e2y ch\u00fang t\u00f4i \u0111\u00e3 gi\u1edbi thi\u1ec7u \u0111\u1ebfn c\u00e1c b\u1ea1n c\u00f4ng th\u1ee9c t\u00ednh chu vi h\u00ecnh tr\u00f2n v\u00e0 b\u00e0i t\u1eadp \u00e1p d\u1ee5ng. Tuy nhi\u00ean, c\u00e1c b\u1ea1n mu\u1ed1n h\u1ecdc t\u1ed1t th\u00ec c\u1ea7n ph\u1ea3i si\u00eang n\u0103ng ch\u0103m ch\u1ec9 nh\u00e9. C\u00e1c b\u1ea1n c\u00f3 th\u1ec3 tham kh\u1ea3o \u0111\u1ec3 c\u00f3 k\u1ebft qu\u1ea3 h\u1ecdc t\u1eadp t\u1ed1t h\u01a1n nh\u00e9. Ch\u00fac c\u00e1c b\u1ea1n th\u00e0nh c\u00f4ng.<\/p>\n","protected":false},"excerpt":{"rendered":"

               C\u00f4ng th\u1ee9c t\u00ednh chu vi h\u00ecnh tr\u00f2n hay di\u1ec7n t\u00edch l\u00e0 m\u1ed9t trong s\u1ed1 nh\u1eefng c\u00f4ng th\u1ee9c m\u00e0 b\u1ea5t k\u1ef3 ai d\u00f9 l\u00e0 h\u1ecdc sinh hay sinh vi\u00ean c\u0169ng c\u1ea7n… <\/p>\n","protected":false},"author":9,"featured_media":9980,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[414,418,407],"tags":[],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/posts\/9976"}],"collection":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/comments?post=9976"}],"version-history":[{"count":0,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/posts\/9976\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/media\/9980"}],"wp:attachment":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/media?parent=9976"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/categories?post=9976"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/tags?post=9976"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}