document.write( "Question 323917: If sin a = 0.2 then cos a must equal? \n" ); document.write( "
Algebra.Com's Answer #231826 by Edwin McCravy(20086)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "If sin a = 0.2 then cos a must equal?\r\n" );
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document.write( "Since \"sine\"\"%22%22=%22%22\"\"%28opposite%29%2F%28hypotenuse%29\" and since\r\n" );
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document.write( "\"0.2\"\"%22%22=%22%22\" the fraction \"0.2%2F1\" if we draw a right triangle\r\n" );
document.write( "with one side equal to the numerator \"0.2\" of that fraction and the\r\n" );
document.write( "hypotenuse equal to the denominator of that fraction \"1\", then the\r\n" );
document.write( "angle that the side that equals \"0.2\" is opposite to will be angle a:\r\n" );
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document.write( "Since \"cosine\"\"%22%22=%22%22\"\"%28adjacent%29%2F%28hypotenuse%29\" all we need\r\n" );
document.write( "do is calculate the side adjacenet to angle a, which is the bottom side,\r\n" );
document.write( "call it x.\r\n" );
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document.write( "We use the Pythagorean theorem to calculate x:\r\n" );
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document.write( "\"adjacent%5E2%2Bopposite%5E2=hypotenuse%5E2\"\r\n" );
document.write( "\"x%5E2%2B%280.2%29%5E2=1%5E2\"\r\n" );
document.write( "\"x%5E2%2B0.04=1\"\r\n" );
document.write( "\"x%5E2=.96\"\r\n" );
document.write( "\"x%5E2=96%2F100\"\r\n" );
document.write( "\"x%5E2=24%2F25\"\r\n" );
document.write( "\"x=sqrt%2824%2F25%29\"\r\n" );
document.write( "\"x=sqrt%2824%29%2Fsqrt%2825%29\"\r\n" );
document.write( "\"x=sqrt%2824%29%2F5\"\r\n" );
document.write( "\"x=sqrt%284%2A6%29%2F5\"\r\n" );
document.write( "\"x=2sqrt%286%29%2F5\"\r\n" );
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document.write( "So \"cos%28a%29\"\"%22%22=%22%22\"\"adjacent%2F%28hypotenuse%29\"\"%22=%22\"\"%282sqrt%286%29%2F5%29%2F1\"\"%22%22=%22%22\"\"2sqrt%286%29%2F5\"\r\n" );
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document.write( "The decimal value of that is 0.9797958971, and you can get that\r\n" );
document.write( "just by using your TI-84 calculator\r\n" );
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document.write( "cos(sin-1(0.2))\r\n" );
document.write( "     .9797958971  \r\n" );
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document.write( "Edwin
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