document.write( "Question 844962: The length of a rectangle is four times its width. If the perimeter of the rectangle is 80cm, find its area. \n" ); document.write( "
Algebra.Com's Answer #509110 by pmesler(52)\"\" \"About 
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We already know that the length is 4 times the width. We can write this as 4w. Next, we need to know the formula for the perimeter of a rectangle. The formulas is this:
\n" ); document.write( "P = 2l + 2w \r
\n" ); document.write( "\n" ); document.write( "From the information given we know that l = 4w, since it states that the length is 4 times the width.\r
\n" ); document.write( "\n" ); document.write( "Next, we simply SUBSTITUTE the value for l into the formula to find the perimeter and that will allow us to solve for w. We know that the perimeter is 80cm so we can just write that,\r
\n" ); document.write( "\n" ); document.write( "80 = 2(4w) + 2w\r
\n" ); document.write( "\n" ); document.write( "Now, let's solve for w. \r
\n" ); document.write( "\n" ); document.write( "80 = 8w + 2w\r
\n" ); document.write( "\n" ); document.write( "80 = 10w\r
\n" ); document.write( "\n" ); document.write( "Divide each side by 10\r
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\n" ); document.write( "\n" ); document.write( "8=w. Therefore the width is 8cm and the length l = 4w or 4(8) = 32 cm.\r
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\n" ); document.write( "\n" ); document.write( "The area of a rectangle is A = L * W. Since we know what the length and width are we simply substitute their values into the equation and we get\r
\n" ); document.write( "\n" ); document.write( "32 * 8 = 256 cm^2. Therefore the area of the rectangle is 256 cm^2. \r
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