C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0 m\u1ed9t c\u00f4ng th\u1ee9c c\u1ef1c k\u1ef3 quan tr\u1ecdng m\u00e0 ch\u00fang ta c\u1ea7n ph\u1ea3i ghi nh\u1edb. Ch\u1ec9 c\u00f3 n\u1eafm \u0111\u01b0\u1ee3c c\u00f4ng th\u1ee9c th\u00ec c\u00e1c b\u1ea1n m\u1edbi c\u00f3 th\u1ec3 l\u00e0m \u0111\u01b0\u1ee3c b\u00e0i t\u1eadp m\u1ed9t c\u00e1ch nhanh nh\u1ea5t v\u00e0 ch\u00ednh x\u00e1c nh\u1ea5t.<\/p>\n

C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh l\u1edbp 4 nhanh nh\u1ea5t<\/h2>\n

H\u00ecnh b\u00ecnh h\u00e0nh l\u00e0 hai t\u1ee9 gi\u00e1c c\u00f3 hai c\u1eb7p c\u1ea1nh \u0111\u1ed1i song song, ho\u1eb7c m\u1ed9t c\u1eb7p c\u1ea1nh \u0111\u1ed1i b\u1eb1ng nhau 2 \u0111\u01b0\u1eddng ch\u00e9o c\u1eaft nhau t\u1ea1i trung \u0111i\u1ec3m c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh<\/p>\n

C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00ednh h\u00ecnh b\u00ecnh h\u00e0nh<\/p>\n

S = axh<\/p>\n

C\u00f4ng th\u1ee9c t\u00ednh chu vi h\u00ecnh b\u00ecnh h\u00e0nh<\/p>\n

Chu vi h\u00ecnh b\u00ecnh h\u00e0nh s\u1ebd b\u1eb1ng hai l\u1ea7n t\u1ed5ng c\u1ee7a 2 c\u1ea1nh k\u1ec1 nhau c =2(a+b)<\/p>\n

Di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh s\u1ebd b\u1eb1ng t\u00edch c\u1ee7a \u0111\u01b0\u1eddng cao nh\u00e2n v\u1edbi c\u1ea1nh \u0111\u00e1y m\u00e0 \u0111\u01b0\u1eddng cao \u0111\u00f3 h\u1ea1 xu\u1ed1ng.<\/p>\n

B\u00e0i t\u1eadp \u00e1p d\u1ee5ng c\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh<\/strong><\/h3>\n

<\/p>\n

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

Cho h\u00ecnh b\u00ecnh h\u00e0nh ABCD c\u00f3 chi\u1ec1u cao h\u1ea1 xu\u1ed1ng c\u1ea1nh CD l\u00e0 5, chi\u1ec1u d\u00e0i CD l\u00e0 15, h\u00e3y t\u00ednh di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh ABCD<\/p>\n

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

S (ABCD) = 5 x 15 = 75 cm^{2<\/sup><\/p>\n}

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

M\u1ea3nh \u0111\u1ea5t h\u00ecnh b\u00ecnh h\u00e0nh c\u00f3 c\u1ea1nh \u0111\u00e1y l\u00e0 47m, m\u1edf r\u1ed9ng m\u1ea3nh \u0111\u1ea5t b\u1eb1ng c\u00e1ch t\u0103ng c\u00e1c c\u1ea1nh \u0111\u00e1y c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh n\u00e0y th\u00eam 7m th\u00ec \u0111\u01b0\u1ee3c m\u1ea3nh \u0111\u1ea5t h\u00ecnh b\u00ecnh h\u00e0nh m\u1edbi c\u00f3 di\u1ec7n t\u00edch h\u01a1n di\u1ec7n t\u00edch m\u1ea3nh \u0111\u1ea5t ban \u0111\u1ea7u l\u00e0 189m^{2<\/sup>. h\u00e3y t\u00ednh di\u1ec7n t\u00edch m\u1ea3nh \u0111\u1ea5t ban \u0111\u1ea7u.<\/p>\n}

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

Ph\u1ea7n di\u1ec7n t\u00edch t\u0103ng th\u00eam ch\u00ednh l\u00e0 di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh c\u00f3 c\u1ea1nh \u0111\u00e1y 7m v\u00e0 chi\u1ec1u cao l\u00e0 chi\u1ec1u cao c\u1ee7a m\u1ea3nh \u0111\u1ea5t h\u00ecnh b\u00ecnh h\u00e0nh ban \u0111\u1ea7u.<\/p>\n

Chi\u1ec1u cao m\u1ea3nh \u0111\u1ea5t l\u00e0: 189 : 7 = 27 (m)<\/p>\n

Di\u1ec7n t\u00edch m\u1ea3nh \u0111\u1ea5t h\u00ecnh b\u00ecnh h\u00e0nh ban \u0111\u1ea7u l\u00e0: 27 x 47 = 1269 (m^{2<\/sup>)<\/p>\n}

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

Cho h\u00ecnh b\u00ecnh h\u00e0nh c\u00f3 chu vi l\u00e0 480cm, c\u00f3 \u0111\u1ed9 d\u00e0i c\u1ea1nh \u0111\u00e1y g\u1ea5p 5 l\u1ea7n c\u1ea1nh kia v\u00e0 g\u1ea5p 8 l\u1ea7n chi\u1ec1u cao. T\u00ednh di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh<\/p>\n

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

– Ta c\u00f3 n\u1eeda chu vi h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0: 480 : 2 = 240 (cm)<\/p>\n

– N\u1ebfu nh\u01b0 coi c\u1ea1nh kia l\u00e0 1 ph\u1ea7n th\u00ec c\u1ea1nh \u0111\u00e1y ch\u00ednh l\u00e0 5 ph\u1ea7n nh\u01b0 v\u1eady.<\/p>\n

Ta c\u00f3 c\u1ea1nh \u0111\u00e1y h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0: 240 : (5+1) x 5 = 200 (cm)<\/p>\n

T\u00ednh \u0111\u01b0\u1ee3c chi\u1ec1u cao c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0: 200 : 8 = 25 (cm)<\/p>\n

Di\u1ec7n t\u00edch c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0: 200 x 25 = 5000 (cm^{2<\/sup>)<\/p>\n}

<\/p>\n

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

Cho h\u00ecnh b\u00ecnh h\u00e0nh c\u00f3 chu vi l\u00e0 364cm v\u00e0 \u0111\u1ed9 d\u00e0i c\u1ea1nh \u0111\u00e1y g\u1ea5p 6 l\u1ea7n c\u1ea1nh kia; g\u1ea5p 2 l\u1ea7n chi\u1ec1u cao. H\u00e3y t\u00ednh di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh \u0111\u00f3<\/p>\n

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

N\u1eeda chu vi h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0: 364 : 2 = 182 (cm)<\/p>\n

C\u1ea1nh \u0111\u00e1y g\u1ea5p 6 l\u1ea7n c\u1ea1nh kia n\u00ean n\u1eeda chu vi s\u1ebd g\u1ea5p 7 l\u1ea7n c\u1ea1nh kia.<\/p>\n

C\u1ea1nh \u0111\u00e1y h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0: 182 : 7 x 6 = 156 (cm)<\/p>\n

Chi\u1ec1u cao h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0: 156 : 2 = 78 (cm)<\/p>\n

Di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0: 156 x 78 = 12168 (cm^{2<\/sup>)<\/p>\n}

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

M\u1ed9t h\u00ecnh b\u00ecnh h\u00e0nh c\u00f3 c\u1ea1nh \u0111\u00e1y l\u00e0 71cm. Ng\u01b0\u1eddi ta thu h\u1eb9p h\u00ecnh b\u00ecnh h\u00e0nh \u0111\u00f3 b\u1eb1ng c\u00e1ch gi\u1ea3m c\u00e1c c\u1ea1nh \u0111\u00e1y c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh \u0111i 19 cm \u0111\u01b0\u1ee3c h\u00ecnh b\u00ecnh h\u00e0nh m\u1edbi c\u00f3 di\u1ec7n t\u00edch nh\u1ecf h\u01a1n di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh ban \u0111\u1ea7u l\u00e0 665cm^{2<\/sup>. T\u00ednh di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh ban \u0111\u1ea7u.<\/p>\n}

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

Ph\u1ea7n di\u1ec7n t\u00edch gi\u1ea3m \u0111i ch\u00ednh l\u00e0 di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh c\u00f3 c\u1ea1nh \u0111\u00e1y l\u00e0 19m v\u00e0 chi\u1ec1u cao l\u00e0 chi\u1ec1u cao m\u1ea3nh \u0111\u1ea5t h\u00ecnh b\u00ecnh h\u00e0nh ban \u0111\u1ea7u.<\/p>\n

Chi\u1ec1u cao h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0: 665 : 19 = 35 (cm)<\/p>\n

Di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh \u0111\u00f3 l\u00e0:<\/p>\n

71 x 35 = 2485 (cm^{2<\/sup>)<\/p>\n}

Tr\u00ean \u0111\u00e2y l\u00e0 c\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh v\u00e0 b\u00e0i t\u1eadp \u00e1p d\u1ee5ng d\u00e0nh cho c\u00e1c b\u1ea1n.<\/p>\n","protected":false},"excerpt":{"rendered":"

C\u00f4ng th\u1ee9c t\u00ednh di\u1ec7n t\u00edch h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0 m\u1ed9t c\u00f4ng th\u1ee9c c\u1ef1c k\u1ef3 quan tr\u1ecdng m\u00e0 ch\u00fang ta c\u1ea7n ph\u1ea3i ghi nh\u1edb. Ch\u1ec9 c\u00f3 n\u1eafm \u0111\u01b0\u1ee3c c\u00f4ng th\u1ee9c th\u00ec… <\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[412,406],"tags":[],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/posts\/9935"}],"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=9935"}],"version-history":[{"count":0,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/posts\/9935\/revisions"}],"wp:attachment":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/media?parent=9935"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/categories?post=9935"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/tags?post=9935"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}