document.write( "Question 1125026: The perimeter of a trapezoid is 39a – 7. Three sides have the following
\n" ); document.write( "lengths: 9a, 5a + 1, and 17a – 6.
\n" ); document.write( "What is the length of the fourth side? \n" ); document.write( "

Algebra.Com's Answer #741364 by MathLover1(20850) $\"\"$ $\"About$

You can put this solution on YOUR website!

\n" ); document.write( "The formula for the perimeter of a trapezoid is \r
\n" ); document.write( "\n" ); document.write( " $\"P=base%5B1%5D+%2B+base+%5B2%5D+%2B+side%5B+a%5D+%2B+side%5B+b%5D\"$ \r
\n" ); document.write( "\n" ); document.write( "given:
\n" ); document.write( " $\"P=39a+-7\"$ Three sides have the following
\n" ); document.write( "lengths:
\n" ); document.write( " $\"side%5B+a%5D=9a\"$ , -> since trapezoid,
\n" ); document.write( " $\"base+%5B2%5D=5a+%2B+1\"$ , and
\n" ); document.write( " $\"base+%5B1%5D=17a+-+6\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"39a+-7=17a+-+6%2B+5a+%2B+1%2B+9a+%2B+side%5B+b%5D\"$ \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " $\"39a+-7-17a+%2B6-5a+-+1-+9a+=+side%5B+b%5D\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"side%5B+b%5D=highlight%288a+-2+%29\"$ ->the length of the fourth side\r
\n" ); document.write( "\n" ); document.write( "check:\r
\n" ); document.write( "\n" ); document.write( "plug it in\r
\n" ); document.write( "\n" ); document.write( " $\"P=base%5B1%5D+%2B+base+%5B2%5D+%2B+side%5B+a%5D+%2B+side%5B+b%5D\"$
\n" ); document.write( " $\"39a+-7=%2817a+-+6%29%2B+%285a+%2B+1%29+%2B+9a%2B+%288a+-2%29\"$
\n" ); document.write( " $\"39a+-7=17a+-+6%2B+5a+%2B+1%2B+9a%2B+8a+-2\"$
\n" ); document.write( " $\"39a+-7=39a+-+7\"$ -> which confirms our solution\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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