Bài 6: Góc
Hướng dẫn giải Bài 1 (Trang 88 SGK Toán 6, Bộ Chân Trời Sáng Tạo, Tập 2)
<p><strong>B&agrave;i 1 (Trang 92 SGK To&aacute;n lớp 6 Tập 2 - Bộ Ch&acirc;n trời s&aacute;ng tạo):</strong></p> <p>Lập bảng thống k&ecirc; c&aacute;c yếu tố của c&aacute;c g&oacute;c trong mỗi h&igrave;nh dưới đ&acirc;y (theo mẫu).</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/13032022/b1-V91Xqw.png" /></p> <table style="border-collapse: collapse; width: 100%;" border="1"> <tbody> <tr> <td style="width: 10.7798%; text-align: center;"><strong>H&igrave;nh</strong></td> <td style="width: 15.8115%; text-align: center;"><strong>T&ecirc;n g&oacute;c</strong></td> <td style="width: 20.6564%; text-align: center;"><strong>Đỉnh</strong></td> <td style="width: 22.7064%; text-align: center;"><strong>Cạnh</strong></td> <td style="width: 30.0459%; text-align: center;"><strong>K&iacute; hiệu g&oacute;c</strong></td> </tr> <tr> <td style="width: 10.7798%; text-align: center;">a)</td> <td style="width: 15.8115%; text-align: center;">g&oacute;c BPC</td> <td style="width: 20.6564%; text-align: center;">P&nbsp;</td> <td style="width: 22.7064%; text-align: center;">PB, PC</td> <td style="width: 30.0459%; text-align: center;"><math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>P</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>B</mi><mi>P</mi><mi>C</mi></mrow><mo>^</mo></mover></math></td> </tr> <tr> <td style="width: 10.7798%; text-align: center;">b)</td> <td style="width: 15.8115%; text-align: center;">&nbsp;</td> <td style="width: 20.6564%; text-align: center;">&nbsp;</td> <td style="width: 22.7064%; text-align: center;">&nbsp;</td> <td style="width: 30.0459%; text-align: center;">&nbsp;</td> </tr> <tr> <td style="width: 10.7798%; text-align: center;">c)</td> <td style="width: 15.8115%; text-align: center;">&nbsp;</td> <td style="width: 20.6564%; text-align: center;">&nbsp;</td> <td style="width: 22.7064%; text-align: center;">&nbsp;</td> <td style="width: 30.0459%; text-align: center;">&nbsp;</td> </tr> </tbody> </table> <p>&nbsp;</p> <p><em><strong>Hướng dẫn giải:</strong></em></p> <p>H&igrave;nh b) tạo bởi ba tia OG, OE, OF chung gốc O tạo ra ba g&oacute;c: G&oacute;c EOF, g&oacute;c FOG, g&oacute;c GOE.</p> <ul> <li>G&oacute;c EOF c&oacute; đỉnh: O, cạnh: OE, OF. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>E</mi><mi>O</mi><mi>F</mi></mrow><mo>^</mo></mover></math>.</li> <li>G&oacute;c FOG c&oacute; đỉnh: O, cạnh: OF, OG. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>F</mi><mi>O</mi><mi>G</mi></mrow><mo>^</mo></mover></math>.</li> <li>G&oacute;c GOE c&oacute; đỉnh: O, cạnh: OG, OE. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>G</mi><mi>O</mi><mi>E</mi></mrow><mo>^</mo></mover></math>.</li> </ul> <p>H&igrave;nh c) tạo bởi c&aacute;c cạnh AB, AC, AD, BC, BD tạo ra t&aacute;m g&oacute;c: G&oacute;c CAD, G&oacute;c ACD, G&oacute;c CAB, G&oacute;c ACB, G&oacute;c ABC, G&oacute;c BAD, G&oacute;c BCD.</p> <ul> <li>G&oacute;c CAD c&oacute; đỉnh: A, cạnh: AC, AD. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>C</mi><mi>A</mi><mi>D</mi></mrow><mo>^</mo></mover><mo>.</mo></math></li> <li>G&oacute;c ACD c&oacute; đỉnh: C, cạnh: AC, AD. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>A</mi><mi>C</mi><mi>D</mi></mrow><mo>^</mo></mover></math>.</li> <li>G&oacute;c CAB c&oacute; đỉnh: A, cạnh: AC, AB. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>C</mi><mi>A</mi><mi>B</mi></mrow><mo>^</mo></mover></math>.</li> <li>G&oacute;c ACB c&oacute; đỉnh: C, cạnh: AC, CB. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>A</mi><mi>C</mi><mi>B</mi></mrow><mo>^</mo></mover></math>.</li> <li>G&oacute;c ABC c&oacute; đỉnh: B, cạnh: AB, AC. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>A</mi><mi>B</mi><mi>C</mi></mrow><mo>^</mo></mover></math>.</li> <li>G&oacute;c BAD c&oacute; đỉnh: A, cạnh: AB, AD. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>B</mi><mi>A</mi><mi>D</mi></mrow><mo>^</mo></mover></math>.</li> <li>G&oacute;c BCD c&oacute; đỉnh: C, cạnh: BC, BD. K&iacute; hiệu: <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mrow><mi>B</mi><mi>C</mi><mi>D</mi></mrow><mo>^</mo></mover></math>.</li> </ul> <p>Ta c&oacute; bảng sau:</p> <table style="border-collapse: collapse; width: 53.9491%;" border="1"> <tbody> <tr> <td style="width: 15.9865%; text-align: center;"><strong>H&igrave;nh</strong></td> <td style="width: 16.7408%; text-align: center;"><strong>T&ecirc;n g&oacute;c</strong></td> <td style="width: 18.5455%; text-align: center;"><strong>Đỉnh</strong></td> <td style="width: 21.6364%; text-align: center;"><strong>Cạnh</strong></td> <td style="width: 27.0909%; text-align: center;"><strong>K&iacute; hiệu g&oacute;c</strong></td> </tr> <tr> <td style="width: 15.9865%; text-align: center;">a)</td> <td style="width: 16.7408%; text-align: center;">BPC</td> <td style="width: 18.5455%; text-align: center;">P</td> <td style="width: 21.6364%; text-align: center;">PB, PC</td> <td style="width: 27.0909%; text-align: center;"><math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>P</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>B</mi><mi>P</mi><mi>C</mi></mrow><mo>^</mo></mover></math></td> </tr> <tr> <td style="width: 15.9865%; text-align: center;">b)</td> <td style="width: 16.7408%; text-align: center;"> <p>EOF</p> <p>FOG</p> <p>GOE</p> </td> <td style="width: 18.5455%; text-align: center;"> <p>O</p> <p>O</p> <p>O</p> </td> <td style="width: 21.6364%; text-align: center;"> <p>OE, OF</p> <p>OF, OG</p> <p>OG, OE</p> </td> <td style="width: 27.0909%; text-align: center;"><math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>O</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>E</mi><mi>O</mi><mi>F</mi></mrow><mo>^</mo></mover><mspace linebreak="newline"/><mover><mi>O</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>F</mi><mi>O</mi><mi>G</mi></mrow><mo>^</mo></mover><mspace linebreak="newline"/><mover><mi>O</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>G</mi><mi>O</mi><mi>E</mi></mrow><mo>^</mo></mover></math></td> </tr> <tr> <td style="width: 15.9865%; text-align: center;">c)</td> <td style="width: 16.7408%; text-align: center;"> <p>CAD</p> <p>ACD</p> <p>ADC</p> <p>CAB</p> <p>ACB</p> <p>ABC</p> <p>BAD</p> <p>BCD</p> </td> <td style="width: 18.5455%; text-align: center;"> <p>A</p> <p>C</p> <p>D</p> <p>A</p> <p>C</p> <p>B</p> <p>A</p> <p>C</p> </td> <td style="width: 21.6364%; text-align: center;"> <p>AC, AD</p> <p>AC, AD</p> <p>AD, AC</p> <p>AC, AB</p> <p>AB, AC</p> <p>AB, AD</p> <p>BC, BD</p> </td> <td style="width: 27.0909%; text-align: center;"><math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>A</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>C</mi><mi>A</mi><mi>D</mi></mrow><mo>^</mo></mover><mspace linebreak="newline"/><mover><mi>C</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>A</mi><mi>C</mi><mi>D</mi></mrow><mo>^</mo></mover><mspace linebreak="newline"/><mover><mi>D</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>A</mi><mi>D</mi><mi>C</mi></mrow><mo>^</mo></mover><mspace linebreak="newline"/><mover><mi>A</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>C</mi><mi>A</mi><mi>B</mi></mrow><mo>^</mo></mover><mspace linebreak="newline"/><mover><mi>C</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>A</mi><mi>C</mi><mi>B</mi></mrow><mo>^</mo></mover><mspace linebreak="newline"/><mover><mi>B</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>A</mi><mi>B</mi><mi>C</mi></mrow><mo>^</mo></mover><mspace linebreak="newline"/><mover><mi>A</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>B</mi><mi>A</mi><mi>D</mi></mrow><mo>^</mo></mover><mspace linebreak="newline"/><mover><mi>C</mi><mo>^</mo></mover><mo>,</mo><mo>&#160;</mo><mover><mrow><mi>B</mi><mi>C</mi><mi>D</mi></mrow><mo>^</mo></mover><mo>.</mo></math></td> </tr> </tbody> </table>
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