document.write( "Question 801765: The diagonals of a rhombus differ by 4. If its perimeter is 40, find its area. \n" ); document.write( "
Algebra.Com's Answer #483626 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
\"10\"= length of one side of the rhombus (because the perimeter, 40, is the sum of 4 such side lengths)
\n" ); document.write( "\"2x\"= length of the shortest diagonal
\n" ); document.write( "\"2x%2B4=2%28x%2B2%29\"= length of the longer diagonal (because it is 4 more than \"2x\")
\n" ); document.write( " The diagonals dplit the rhombus into 4 congruent triangles.
\n" ); document.write( "Applying the Pythagorean theorem to one of those 4 triangles, we get
\n" ); document.write( "\"x%5E2%2B%28x%2B2%29%5E2=10%5E2\"
\n" ); document.write( "\"x%5E2%2Bx%5E2%2B4x%2B4=100\"
\n" ); document.write( "\"2x%5E2%2B4x%2B4=100\"
\n" ); document.write( "\"2x%5E2%2B4x-96=0\"
\n" ); document.write( "Dividing both sides of the equal sign by 2, the equation simplifies to
\n" ); document.write( "\"x%5E2%2B2x-48=0\"
\n" ); document.write( "Solving by factoring is easy.
\n" ); document.write( "Factoring we get
\n" ); document.write( "\"%28x%2B8%29%28x-6%29=0\" with solutions \"x=-8\" and \"x=6\"
\n" ); document.write( "Since a negative length does not make sense the solution is
\n" ); document.write( "\"x=6\", which makes \"x%2B2=8\"
\n" ); document.write( "The area of the rhombus is the area of the 4 triangles
\n" ); document.write( "\"2%2A6%2A8=highlight%2896%29\"
\n" ); document.write( "
\n" ); document.write( "
\n" );