document.write( "Question 640990: The sides of a triangle are in the ratio of 4:5:6. Find the size of the largest angle in the triangle. \n" ); document.write( "

Algebra.Com's Answer #403510 by Edwin McCravy(20056) $\"\"$ $\"About$

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The sides of a triangle are in the ratio of 4:5:6. Find the size of the largest angle in the triangle.\r
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document.write( "The angles will be the same no matter what sides we use, and long as\r\n" );
document.write( "they are in the ration 4:5:6.  So we may as well take the easiest situation,\r\n" );
document.write( "which is to assume the sides of the triangle are a=4, b=5 and c=6.\r\n" );
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document.write( "The largest angle C will be opposite the largest sides, c=6, so we use \r\n" );
document.write( "the law of cosines for c. We solve for angle C\r\n" );
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document.write( "          c² = a² + b² - 2·a·b·cos(C)\r\n" );
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document.write( "2·a·b·cos(C) = a² + b² - c² \r\n" );
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document.write( "      cos(C) = \r\n" );
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document.write( "      cos(C) = \r\n" );
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document.write( "      cos(C) = \r\n" );
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document.write( "      cos(C) = \r\n" );
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document.write( "      cos(C) = \r\n" );
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document.write( "          C = 82.81924422° which I suppose you'd round off to 82.8°\r\n" );
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document.write( "Edwin

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