Bài 2: Diện Tích Hình Chữ Nhật
Hướng dẫn giải Bài 10 (Trang 119 SGK Toán Hình học 8, Tập 1)
<p><strong class="content_question">Đề b&agrave;i</strong></p> <p>Cho một tam gi&aacute;c vu&ocirc;ng. H&atilde;y so s&aacute;nh tổng diện t&iacute;ch của hai h&igrave;nh vu&ocirc;ng dựng tr&ecirc;n hai g&oacute;c vu&ocirc;ng với diện t&iacute;ch h&igrave;nh vu&ocirc;ng dựng tr&ecirc;n cạnh huyền.</p> <p><strong class="content_detail">Lời giải chi tiết</strong></p> <p><img src="https://img.loigiaihay.com/picture/2018/0716/b10-trang-119-sgk-toan-8-t-1-c2.jpg" alt="" /></p> <p>Giả sử tam gi&aacute;c vu&ocirc;ng&nbsp;<span id="MathJax-Element-1-Frame" class="mjx-chtml MathJax_CHTML" style="margin: 0px; padding: 1px 0px; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: 400; font-size: 16.94px; letter-spacing: normal; overflow-wrap: normal; word-spacing: 0px; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; color: #000000; font-family: OpenSans, Tahoma, Helvetica, sans-serif; font-variant-ligatures: normal; font-variant-caps: normal; orphans: 2; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/math&gt;"><span id="MJXc-Node-1" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-2" class="mjx-mrow"><span id="MJXc-Node-3" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I">A</span></span><span id="MJXc-Node-4" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I">B</span></span><span id="MJXc-Node-5" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I">C</span></span></span></span></span>&nbsp;c&oacute; cạnh huyền l&agrave;&nbsp;<span id="MathJax-Element-2-Frame" class="mjx-chtml MathJax_CHTML" style="margin: 0px; padding: 1px 0px; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: 400; font-size: 16.94px; letter-spacing: normal; overflow-wrap: normal; word-spacing: 0px; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; color: #000000; font-family: OpenSans, Tahoma, Helvetica, sans-serif; font-variant-ligatures: normal; font-variant-caps: normal; orphans: 2; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/math&gt;"><span class="MJX_Assistive_MathML" role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi></math></span></span>&nbsp;v&agrave; hai cạnh g&oacute;c vu&ocirc;ng l&agrave;&nbsp;<span id="MathJax-Element-3-Frame" class="mjx-chtml MathJax_CHTML" style="margin: 0px; padding: 1px 0px; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: 400; font-size: 16.94px; letter-spacing: normal; overflow-wrap: normal; word-spacing: 0px; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; color: #000000; font-family: OpenSans, Tahoma, Helvetica, sans-serif; font-variant-ligatures: normal; font-variant-caps: normal; orphans: 2; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/math&gt;"><span id="MJXc-Node-9" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-10" class="mjx-mrow"><span id="MJXc-Node-11" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I">b</span></span><span id="MJXc-Node-12" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R">,</span></span><span id="MJXc-Node-13" class="mjx-mi MJXc-space1"><span class="mjx-char MJXc-TeX-math-I">c</span></span></span></span></span>&nbsp;(như h&igrave;nh vẽ)<br />Diện t&iacute;ch h&igrave;nh vu&ocirc;ng dựng tr&ecirc;n cạnh huyền a l&agrave; <math xmlns="http://www.w3.org/1998/Math/MathML"><mstyle displaystyle="false"><msup><mi>a</mi><mn>2</mn></msup></mstyle></math><br />Diện t&iacute;ch h&igrave;nh vu&ocirc;ng dựng tr&ecirc;n cạnh g&oacute;c vu&ocirc;ng b l&agrave; <math xmlns="http://www.w3.org/1998/Math/MathML"><mstyle displaystyle="false"><msup><mi>b</mi><mn>2</mn></msup></mstyle></math><br />Diện t&iacute;ch h&igrave;nh vu&ocirc;ng dựng tr&ecirc;n cạnh g&oacute;c vu&ocirc;ng c l&agrave; <math xmlns="http://www.w3.org/1998/Math/MathML"><mstyle displaystyle="false"><msup><mi>c</mi><mn>2</mn></msup></mstyle></math><br />&Aacute;p dụng định l&iacute; Pitago v&agrave;o tam gi&aacute;c vu&ocirc;ng ABC vu&ocirc;ng tại A ta c&oacute;: <math xmlns="http://www.w3.org/1998/Math/MathML"><mstyle displaystyle="false"><msup><mi>a</mi><mn>2</mn></msup><mo>=</mo><msup><mi>b</mi><mn>2</mn></msup><mo>+</mo><msup><mi>c</mi><mn>2</mn></msup></mstyle></math><br /><br /><br /></p>
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