document.write( "Question 954558: The perimeter of a rectangle is 30 inches. If its length is three times its width, find the dimensions \n" ); document.write( "

Algebra.Com's Answer #583008 by aYummyNoodle(10) $\"\"$ $\"About$

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We can assign the variable $\"x\"$ and $\"y\"$ to the length and width of the rectangle. In this case, I will assign $\"x\"$ to the length and $\"y\"$ to the width of the rectangle. As the length is three times its width, the equation would be:
\n" ); document.write( " $\"x=3y\"$ .
\n" ); document.write( "Finding the perimeter of a rectangle is always the sum of two times the length and two times the width. $\"P\"$ stands for perimeter in this equation. That is:
\n" ); document.write( " $\"P=2x%2B2y\"$ .
\n" ); document.write( "In the first equation, we already have $\"x\"$ isolated, we can plug it in to the second equation. We know that the perimeter is 30, so we can also plug that in for $\"P\"$ .
\n" ); document.write( " $\"30=2%283y%29%2B2y\"$ .
\n" ); document.write( "Simplifying us would give us
\n" ); document.write( " $\"30=6y%2B2y\"$
\n" ); document.write( " $\"30=8y\"$ .
\n" ); document.write( " $\"y=3.75\"$
\n" ); document.write( "So now we know that the width of the rectangle is 3.75.
\n" ); document.write( "We can now plug this back in to the original equation to get:
\n" ); document.write( " $\"x=3%283.75%29\"$
\n" ); document.write( " $\"x=11.25\"$ .
\n" ); document.write( "So the answer is Length=11.25 and Width=3.75. \n" ); document.write( "

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