SOLUTION: The length of a rectangle is 3 times it's width. it's perimeter is 56cm. what is the area of the rectangle?

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Question 522788: The length of a rectangle is 3 times it's width. it's perimeter is 56cm. what is the area of the rectangle?
Answer by umnikmo(75) About Me  (Show Source):
You can put this solution on YOUR website!
P=2(L+W)
L=3W
P=2(W+3W)=8W=56 =>W=7
L=3W=21
S=WL=21*7=147