document.write( "Question 1205848: Given ABCD is a trapezoid with BC parallel to AD. If AB = AD = 4, angle A = 60 degrees, and angle C = 45 degrees, determine the value of length DC. \n" ); document.write( "
Algebra.Com's Answer #842912 by Edwin McCravy(20054)\"\" \"About 
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document.write( "I labeled the trapezoid clockwise instead of counter-clockwise. To make\r\n" );
document.write( "it labeled counter-clockwise, draw the mirror image of this drawing.\r\n" );
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document.write( "Braw BE and FD perpendicular to AD and BC.\r\n" );
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document.write( "\"AE%2FAB=cos%28%22%3CA%22%29\"\r\n" );
document.write( "\"AE=AB%2Acos%28%22%3CA%22%29=4%2Acos%2860%5Eo%29=4%281%2F2%29=2\"\r\n" );
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document.write( "\"EB%2FAB=sin%28%22%3CA%22%29\"\r\n" );
document.write( "\"EB=AB%2Asin%28%22%3CA%22%29=4%2Asin%2860%5Eo%29=4%28sqrt%283%29%2F2%29=2sqrt%283%29\"\r\n" );
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document.write( "\"ED=AD-AE=4-2=2\"\r\n" );
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document.write( "\"BF=ED=2\"\r\n" );
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document.write( "\"DF=EB=2sqrt%283%29\"\r\n" );
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document.write( "Since angle C is 45o, that tells us that triangle DFC is an\r\n" );
document.write( "isosceles right triangle. The hyptenuse of an isosceles right triangle is\r\n" );
document.write( "\"sqrt%282%29\" times either leg.\r\n" );
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document.write( "\"DC+=+DF%2Asqrt%283%29+=+2sqrt%283%29%2Asqrt%282%29=2sqrt%286%29+\"\r\n" );
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document.write( "Edwin

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