SOLUTION: The length of a rectangle is twice the width. The perimeter is 36 units. What are the length and width?

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Question 47164: The length of a rectangle is twice the width. The perimeter is 36 units. What are the length and width?
Answer by mszlmb(115)   (Show Source): You can put this solution on YOUR website!
perimeter=2length+2width

2width=1length.

ok let's replace width with w and length with l.  It is also safe to replace perimeter with 36 as that is its value.

36=2l+2w
2w=l

so let's substitute l with 2w in the first problem.

36=2(2w)+2w   simplify
36=6w         divide by 6, both sides
6=w

back to second equation:
2w=l

2(6)=l
12=l

length=12
width=6.
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