Hình tam giác. Diện tích hình tam giác

Home Lớp 5 Toán lớp 5 - Sách Kết nối tri thức Bài 25. Hình tam giác. Diện tích hình tam giác.Bài tập nâng cao

{"common":{"save":0,"post_id":"7695","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"1773","post_id":"7695","mon_id":"1159414","chapter_id":"1159460","question":"Khi t\u0103ng chi\u1ec1u cao c\u1ee7a m\u1ed9t tam giác lên 4 l\u1ea7n, \u0111\u1ed9 dài \u0111áy gi\u1ea3m \u0111i 2 l\u1ea7n. Khi \u0111ó di\u1ec7n tích c\u1ee7a tam giác \u0111ó thay \u0111\u1ed5i nh\u01b0 th\u1ebf nào?<\/p>","options":["A.<\/strong> Không \u0111\u1ed5i","B.<\/strong> T\u0103ng 4 l\u1ea7n","C.<\/strong> Gi\u1ea3m 2 l\u1ea7n","D.<\/strong> T\u0103ng 2 l\u1ea7n"],"correct":"4","level":"3","hint":"","answer":"Ch\u1ecdn D.<\/strong> T\u0103ng 2 l\u1ea7n.<\/span><\/p>Khi t\u0103ng chi\u1ec1u cao c\u1ee7a m\u1ed9t tam giác lên 4 l\u1ea7n thì di\u1ec7n tích hình tam giác t\u0103ng lên 4 l\u1ea7n, \u0111\u1ed9 dài \u0111áy gi\u1ea3m \u0111i 2 l\u1ea7n thì di\u1ec7n tích hình tam giác gi\u1ea3m 2 l\u1ea7n.<\/p>V\u1eady sau khi t\u0103ng 4 l\u1ea7n và gi\u1ea3m 2 l\u1ea7n thì di\u1ec7n tích hình tam giác \u0111ó t\u0103ng lên 4 : 2 = 2 (l\u1ea7n).<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"0","date":"2024-09-22 02:56:13","option_type":"txt","len":2},{"id":"1776","post_id":"7695","mon_id":"1159414","chapter_id":"1159460","question":"Cho hình v\u1ebd d\u01b0\u1edbi \u0111ây. Tính di\u1ec7n tích tam giác EDC bi\u1ebft hình ch\u1eef nh\u1eadt ABCD có AB = 47cm; BC = 34 cm.<\/p><svg height=\"180\" width=\"250\"> <g><title><\/title><rect fill=\"#aaaaff\" height=\"182\" id=\"canvas_background\" width=\"252\" x=\"-1\" y=\"-1\"><\/rect> <g display=\"none\" id=\"canvasGrid\"> <rect fill=\"url(#gridpattern)\" height=\"100%\" id=\"svg_9\" stroke-width=\"0\" width=\"100%\" x=\"0\" y=\"0\"><\/rect> <\/g> <\/g> <g><title><\/title><rect fill=\"#ffffaa\" height=\"126\" id=\"svg_1\" stroke=\"#000\" stroke-width=\"1.5\" width=\"182\" x=\"38.5\" y=\"25.25\"><\/rect> <line fill=\"none\" id=\"svg_2\" stroke=\"#000\" stroke-linecap=\"null\" stroke-linejoin=\"null\" stroke-opacity=\"null\" stroke-width=\"1.5\" x1=\"100\" x2=\"39\" y1=\"25.25\" y2=\"151.25\"><\/line> <line fill=\"none\" fill-opacity=\"null\" id=\"svg_3\" stroke=\"#000\" stroke-linecap=\"null\" stroke-linejoin=\"null\" stroke-opacity=\"null\" stroke-width=\"1.5\" x1=\"99\" x2=\"220\" y1=\"25.25\" y2=\"150.25\"><\/line> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_4\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"17\" xml:space=\"preserve\" y=\"29.25\">A<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_5\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"90\" xml:space=\"preserve\" y=\"20.25\">E<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_6\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"220\" xml:space=\"preserve\" y=\"23.25\">B<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_7\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"223\" xml:space=\"preserve\" y=\"162.25\">C<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_8\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"18\" xml:space=\"preserve\" y=\"161.25\">D<\/text> <\/g> <\/svg><\/span><\/p>","options":["A.<\/strong> 899 cm²","B.<\/strong> 799 cm²","C.<\/strong> 889 cm²","D.<\/strong> 899 cm²"],"correct":"2","level":"3","hint":"","answer":"Ch\u1ecdn B.<\/strong> 799 cm².<\/span><\/p><svg height=\"180\" width=\"250\"> <g><title><\/title><rect fill=\"#aaaaff\" height=\"182\" id=\"canvas_background\" width=\"252\" x=\"-1\" y=\"-1\"><\/rect> <g display=\"none\" id=\"canvasGrid\"> <rect fill=\"url(#gridpattern)\" height=\"100%\" id=\"svg_9\" stroke-width=\"0\" width=\"100%\" x=\"0\" y=\"0\"><\/rect> <\/g> <\/g> <g><title><\/title><rect fill=\"#ffffaa\" height=\"126\" id=\"svg_1\" stroke=\"#000\" stroke-width=\"1.5\" width=\"182\" x=\"38.5\" y=\"25.25\"><\/rect> <line fill=\"none\" id=\"svg_2\" stroke=\"#000\" stroke-linecap=\"null\" stroke-linejoin=\"null\" stroke-opacity=\"null\" stroke-width=\"1.5\" x1=\"100\" x2=\"39\" y1=\"25.25\" y2=\"151.25\"><\/line> <line fill=\"none\" fill-opacity=\"null\" id=\"svg_3\" stroke=\"#000\" stroke-linecap=\"null\" stroke-linejoin=\"null\" stroke-opacity=\"null\" stroke-width=\"1.5\" x1=\"99\" x2=\"220\" y1=\"25.25\" y2=\"150.25\"><\/line> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_4\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"17\" xml:space=\"preserve\" y=\"29.25\">A<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_5\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"90\" xml:space=\"preserve\" y=\"20.25\">E<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_6\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"220\" xml:space=\"preserve\" y=\"23.25\">B<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_7\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"223\" xml:space=\"preserve\" y=\"162.25\">C<\/text> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_8\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"18\" xml:space=\"preserve\" y=\"161.25\">D<\/text> <line fill=\"none\" id=\"svg_10\" stroke=\"#000\" stroke-linecap=\"undefined\" stroke-linejoin=\"undefined\" stroke-width=\"1.5\" x1=\"99.5\" x2=\"99.5\" y1=\"24.25\" y2=\"150\"><\/line> <text fill=\"#000000\" fill-opacity=\"null\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_11\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"93.5\" xml:space=\"preserve\" y=\"174.25\">F<\/text> <rect fill=\"none\" fill-opacity=\"null\" height=\"15\" id=\"svg_12\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"1.5\" width=\"15\" x=\"99.5\" y=\"135.25\"><\/rect> <\/g> <\/svg><\/span><\/p>K\u1ebb EF vuông góc v\u1edbi CD, khi \u0111ó EF là chi\u1ec1u cao t\u01b0\u01a1ng \u1ee9ng v\u1edbi c\u1ea1nh \u0111áy CD. Ta có chi\u1ec1u cao EF b\u1eb1ng chi\u1ec1u r\u1ed9ng c\u1ee7a hình ch\u1eef nh\u1eadt ABCD hay EF = BC = 34 cm. Vì ABCD là hình ch\u1eef nh\u1eadt nên AB = CD = 47 cm. Di\u1ec7n tích tam giác EDC là: $\\dfrac{47\\times34}{2}=799$<\/span> (cm²).<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"0","date":"2024-09-22 03:03:48","option_type":"txt","len":1},{"id":"1777","post_id":"7695","mon_id":"1159414","chapter_id":"1159460","question":"M\u1ed9t trang tr\u1ea1i nh\u1ecf có chu vi 86m, chi\u1ec1u dài 28m. \u1ede gi\u1eefa trang tr\u1ea1i, ng\u01b0\u1eddi ta xây m\u1ed9t cái ao cá hình tam giác có chi\u1ec1u cao 9,6 m và c\u1ea1nh \u0111áy b\u1eb1ng $\\dfrac{5}{3}$<\/span> chi\u1ec1u cao, ph\u1ea7n còn l\u1ea1i \u0111\u1ec3 tr\u1ed3ng rau và hoa. Di\u1ec7n tích ph\u1ea7n tr\u1ed3ng rau và hoa là:<\/p>","options":["A.<\/strong> 343,2 m²","B.<\/strong> 334,2 m²","C.<\/strong> 324,2 m²","D.<\/strong> 332,2 m²"],"correct":"1","level":"3","hint":"","answer":"Ch\u1ecdn A.<\/strong> 343,2 m².<\/span><\/p>N\u1eeda chu vi trang tr\u1ea1i hình ch\u1eef nh\u1eadt \u0111ó là 86 : 2 = 43 (m). Chi\u1ec1u r\u1ed9ng trang tr\u1ea1i là: 43 – 28 = 15 (m). Di\u1ec7n tích mi\u1ebfng \u0111\u1ea5t hình ch\u1eef nh\u1eadt \u0111ó là: 28 x 15 = 420 (m²).<\/p>\u0110\u1ed9 dài c\u1ea1nh \u0111áy c\u1ee7a ao cá là: $9,6\\times\\dfrac{5}{3}=16$<\/span> (m).<\/p>Di\u1ec7n tích ao cá hình tam giác \u0111ó là: 16 x 9,6 : 2 = 76,8 (m²). Di\u1ec7n tích ph\u1ea7n tr\u1ed3ng rau và hoa là: 420 – 76,8 = 343,2 (m²).<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"0","date":"2024-09-22 03:09:04","option_type":"txt","len":2}]}