document.write( "Question 333343: Two rectangles have the same area of 480 cm^2.the diffrence between their lengths is 5cm and the diffrence between their widths is 2cm . calculate the dimension of the rectangles \n" ); document.write( "
Algebra.Com's Answer #238910 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! Two rectangles have the same area of 480 cm^2. \n" ); document.write( "the difference between their lengths is 5cm and the difference between their widths is 2cm. \n" ); document.write( " calculate the dimension of the rectangles \n" ); document.write( ": \n" ); document.write( "Let the dimension of the original rectangle be L, W \n" ); document.write( "L*W = 480 \n" ); document.write( "L = \n" ); document.write( ": \n" ); document.write( "the dimensions of the other rectangle be (L-5), (w+2) \n" ); document.write( ": \n" ); document.write( "Areas of the two rectangles are equal \n" ); document.write( "(L-5)*(W+2) = L*W \n" ); document.write( "FOIL \n" ); document.write( "LW + 2L - 5W - 10 = LW \n" ); document.write( ": \n" ); document.write( "Subtract LW from both sides \n" ); document.write( "2L - 5W - 10 = 0 \n" ); document.write( ": \n" ); document.write( "Replace L with \n" ); document.write( "2( \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( "Multiply by W \n" ); document.write( "960 - 5W^2 - 10W = 0 \n" ); document.write( "; \n" ); document.write( "a quadratic equation \n" ); document.write( "-5W^2 - 10w + 960 = 0 \n" ); document.write( ": \n" ); document.write( "simplify, divide by -5 \n" ); document.write( "W^2 + 2W - 192 = 0 \n" ); document.write( ": \n" ); document.write( "Find W using the quadratic formula \n" ); document.write( " \n" ); document.write( "in this equation: x=w; a=1; b=2; c=-192 \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "two solutions, but we just want the positive solution \n" ); document.write( " \n" ); document.write( "w = \n" ); document.write( "w = 12.89 cm, the width of the original rectangle \n" ); document.write( "then \n" ); document.write( " \n" ); document.write( "Check area: 12.89*37.24 = 480.02 \n" ); document.write( ": \n" ); document.write( "The other rectangle \n" ); document.write( "12.89 + 2 = 14.89 is the width \n" ); document.write( "37.24 - 5 = 32.24 is the length \n" ); document.write( "check area: 14.89*32.24 = 480.05, close enough to confirm our solutions \n" ); document.write( " |