document.write( "Question 1153291: Find the number of sides of a polygon if the sum of the number of sides and the number of diagonals is 66.
\n" ); document.write( "A. 11
\n" ); document.write( "B. 12
\n" ); document.write( "C. 14
\n" ); document.write( "D. 16
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Algebra.Com's Answer #775481 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
\r
\n" ); document.write( "\n" ); document.write( "total number of diagonals: \"n%28n-3%29%2F2\" where\"+n\" is the number of \"sides\"\r
\n" ); document.write( "\n" ); document.write( "if the sum of the number of \"sides\" and the number of \"diagonals\" is \"66\", we have\r
\n" ); document.write( "\n" ); document.write( "\"n%2Bn%28n-3%29%2F2=66\"\r
\n" ); document.write( "\n" ); document.write( "\"%282n%2Bn%5E2-3n%29%2F2=66\"\r
\n" ); document.write( "\n" ); document.write( "\"n%5E2-n=132\"\r
\n" ); document.write( "\n" ); document.write( "\"n%5E2-n-132=0\"...factor completely\r
\n" ); document.write( "\n" ); document.write( "\"n%5E2%2B11n-12n-132=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28n%5E2%2B11n%29-%2812n%2B132%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"n%28n%2B11%29-12%28n%2B11%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28n+-+12%29+%28n+%2B+11%29+=+0\"\r
\n" ); document.write( "\n" ); document.write( "solutions:\r
\n" ); document.write( "\n" ); document.write( "\"n=12\"
\n" ); document.write( "\"n=-11\"-> disregard negative solution\r
\n" ); document.write( "\n" ); document.write( " the number of sides is \"12\"\r
\n" ); document.write( "\n" ); document.write( "answer: B. \"12\"
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