document.write( "Question 319932: What is the circumference of a circle if the area is \"81pi\"? \n" ); document.write( "
Algebra.Com's Answer #229121 by Edwin McCravy(20055)\"\" \"About 
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What is the circumference of a circle if the area is \"81pi\"?
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document.write( "Use the Area formula \"A=pi%2Ar%5E2\" to find the radius; then use that\r\n" );
document.write( "value for r in the circumference formula \"C=2pi%2Ar\". \r\n" );
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document.write( "\"A+=+pi%2Ar%5E2\"\r\n" );
document.write( "\"81pi=pi%2Ar%5E2\"\r\n" );
document.write( "\"%2881pi%29%2Fpi=pi%2Ar%5E2%2Fpi\"\r\n" );
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document.write( "\"%2881cross%28pi%29%29%2Fcross%28pi%29=cross%28pi%29%2Ar%5E2%2Fcross%28pi%29\"\r\n" );
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document.write( "\"81=r%5E2\"\r\n" );
document.write( "\"sqrt%2881%29=sqrt%28r%5E2%29\"\r\n" );
document.write( "\"9=r\"\r\n" );
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document.write( "\"C+=+2pi%2Ar\"\r\n" );
document.write( "\"C+=+2pi%2A9\"\r\n" );
document.write( "\"C=18pi\"\r\n" );
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document.write( "Edwin
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