{"article_info":{"article_id":142097,"cat_id":1392,"cat_title":"SGK Toán 8 - Cánh diều","publish_time":1687247760,"cat_id2":1392,"is_link":0,"thumbnail":"https://img.loigiaihay.com/picture/article/2023/0620/resize_1-0_51.png","title":"Giải bài 4 trang 57 SGK Toán 8 – Cánh diều","label":"Bài 4 trang 57","alias":"giai-bai-4-trang-57-sgk-toan-8-canh-dieu","introtext":"Trong Hình 16, độ dài đoạn thẳng A’C’ mô tả chiều cao của một cái cây","content":"<style>\r\n.method-close-icon{position: relative;float: right;top: 6px;transform: rotate(270deg);-ms-transform:rotate(270deg);-moz-transform:rotate(270deg);-webkit-transform:rotate(270deg);-o-transform:rotate(270deg);}\r\n.method-open-icon{position: relative;float: right;top: 6px;}\r\n</style>\r\n<p><strong style=\"font-size: 16px;\">Đề bài</strong></p><p>Trong <em>Hình 16</em>, độ dài đoạn thẳng A’C’ mô tả chiều cao của một cái cây, đoạn thẳng AC mô tả một cái cọc (cây và cọc cùng vuông góc với đường thẳng đi qua ba điểm A’, A, B). Giả sử \\(AC = 2m,\\,\\,AB = 1,5m,\\,\\,A'B = 4,5m\\). Tính chiều cao của cây.</p>\r\n<p><img src=\"https://img.loigiaihay.com/picture/2023/0620/1_60.png\" /></p><div id=\"pos_end_question\"></div><div style=\"padding-top: 10px;padding-bottom: 2px;margin-bottom: 10px;\"><p class=\"show-detail-method\" style=\"background: #654bc2;text-align: center;border-radius:5px;padding: 10px;margin-bottom: 0px;\" onclick=\"showDetailMethod();\"><strong style=\"font-size: 16px;\">Phương pháp giải - Xem chi tiết</strong><img class=\"method-open-icon\" id=\"method_colapse_icon\" src=\"data:image/png;base64,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\"></p>  <div class=\"content_method_content\" style=\"padding: 10px 10px 5px 10px;border: dashed 1px #654bc2;border-top:none;\"><p>-         Chứng minh \\(AC\\parallel A'C'\\).</p>\r\n<p>-         Dựa vào hệ quả của định lý Thales để tính độ dài A’C’.</p>  </div>\r\n<script type=\"text/javascript\">\r\n    var is_open =true;\r\n    function showDetailMethod(){\r\n        if(is_open){\r\n            document.querySelector(\".content_method_content\").style.display='none';\r\n            document.getElementById(\"method_colapse_icon\").classList.remove(\"method-open-icon\");\r\n            document.getElementById(\"method_colapse_icon\").classList.add(\"method-close-icon\");\r\n        }else{\r\n            document.querySelector(\".content_method_content\").style.display='block';\r\n            document.getElementById(\"method_colapse_icon\").classList.remove(\"method-close-icon\");\r\n            document.getElementById(\"method_colapse_icon\").classList.add(\"method-open-icon\");\r\n        }\r\n        is_open = !is_open;\r\n    }\r\n</script>\r\n</div><p><strong style=\"font-size: 16px;\">Lời giải chi tiết</strong></p><p>\\(\\left. \\begin{array}{l}AC \\bot A'B\\\\A'C' \\bot A'B\\end{array} \\right\\} \\Rightarrow AC\\parallel A'C'\\)</p>\r\n<p>Xét tam giác A’BC’ với \\(AC\\parallel A'C'\\) có:</p>\r\n<p>\\(\\frac{{AC}}{{A'C'}} = \\frac{{BA}}{{BA'}}\\) (Hệ quả của định lý Thales)</p>\r\n<p>\\( \\Rightarrow \\frac{{AC}}{{A'C'}} = \\frac{{1,5}}{{4,5}} = \\frac{1}{3} \\Rightarrow A'C' = 3AC = 6m\\)</p>\r\n<p>Vậy cây cao 6m.</p>","common_article":"","display_type":1,"vungoi_exam_id":"","article_type":1,"cmt_count":0,"zip_status":1,"last_modified_time":1703041979,"last_zip_time":1703041979,"zip_link":"https://offline.loigiaihay.com/articles/1392/142097/142097_1703041979.zip","picture":"https://img.loigiaihay.com/picture/article/2023/0620/1-0_51.png","youtube_id":"x4wrmJKu4_0","video_start_time":"3957","quizlet_id":"0","ref_article_id":0,"readmore_display_type":0,"wiki":0,"comment_url":"https://loigiaihay.com/comment/giai-bai-4-trang-57-sgk-toan-8-canh-dieu-c1392a142097.html","origin_url":"https://loigiaihay.com/giai-bai-4-trang-57-sgk-toan-8-canh-dieu-c1392a142097.html","relate_link":[],"exam_file":"","solution_file":""},"callouts":[],"relate_articles":[],"others_in_cat":[{"article_id":142099,"cat_id":1392,"publish_time":1687247940,"is_link":0,"thumbnail":"https://img.loigiaihay.com/picture/article/2023/0620/resize_1-0_52.png","title":"Giải bài 5 trang 57 SGK Toán 8 – Cánh diều","alias":"giai-bai-5-trang-57-sgk-toan-8-canh-dieu","introtext":"Cho đoạn thẳng AB. Hãy trình bày cách chia đoạn thẳng AB thành ba đoạn thẳng bằng nhau mà không cần dùng thước đo.","display_type":1,"article_type":1},{"article_id":142095,"cat_id":1392,"publish_time":1687247640,"is_link":0,"thumbnail":"https://img.loigiaihay.com/picture/article/2023/0620/resize_1-0_50.png","title":"Giải bài 3 trang 57 SGK Toán 8 – Cánh diều","alias":"giai-bai-3-trang-57-sgk-toan-8-canh-dieu","introtext":"Trong Hình 15, cho ","display_type":1,"article_type":1},{"article_id":142094,"cat_id":1392,"publish_time":1687247520,"is_link":0,"thumbnail":"https://img.loigiaihay.com/picture/article/2023/0620/resize_1-0_49.png","title":"Giải bài 2 trang 57 SGK Toán 8 – Cánh diều","alias":"giai-bai-2-trang-57-sgk-toan-8-canh-dieu","introtext":"Cho hình thang ABCD ","display_type":1,"article_type":1},{"article_id":142093,"cat_id":1392,"publish_time":1687247400,"is_link":0,"thumbnail":"https://img.loigiaihay.com/picture/article/2023/0620/resize_1-0_48.png","title":"Giải bài 1 trang 57 SGK Toán 8 – Cánh diều","alias":"giai-bai-1-trang-57-sgk-toan-8-canh-dieu","introtext":"Cho tam giác ABC có ","display_type":1,"article_type":1},{"article_id":142092,"cat_id":1392,"publish_time":1687247040,"is_link":0,"thumbnail":"https://img.loigiaihay.com/picture/article/2023/0620/resize_1-0_47.png","title":"Giải mục 2 trang 53, 54, 55 SGK Toán 8 – Cánh diều","alias":"giai-muc-2-trang-53-54-55-sgk-toan-8-canh-dieu","introtext":"Quan sát Hình 3 và cho biết:","display_type":2,"article_type":1},{"article_id":142091,"cat_id":1392,"publish_time":1687246620,"is_link":0,"thumbnail":"https://img.loigiaihay.com/picture/article/2023/0620/resize_1-0_46.png","title":"Giải mục 1 trang 52 SGK Toán 8 – Cánh diều","alias":"giai-muc-1-trang-52-sgk-toan-8-canh-dieu","introtext":"Cho hai đoạn thẳng AB = 2cm, CD = 3cm và hai đoạn thẳng MN = 4cm, PQ = 6cm.","display_type":1,"article_type":1},{"article_id":144159,"cat_id":1392,"publish_time":1689150120,"is_link":0,"thumbnail":"https://img.loigiaihay.com/picture/article/2023/0712/resize_1-0_28.png","title":"Lý thuyết Định lí Thalès trong tam giác SGK Toán 8 - Cánh diều","alias":"ly-thuyet-dinh-li-thales-trong-tam-giac-sgk-toan-8-canh-dieu","introtext":"Định lí Thalès là gì?","display_type":0,"article_type":1}],"event_info":{"title":"Bài 1. 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