SOLUTION: The length of a rectangle is five times its width. If the area of the rectangle is 450 cm^2 find its perimeter.

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Question 461709: The length of a rectangle is five times its width.
If the area of the rectangle is 450 cm^2 find its perimeter.

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

The length L of a rectangle is five times its width W.
L=5W.........1
If the area of the rectangle A=L%2AW=450+cm%5E2 .....2
find its perimeter P
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P=2%28L%2BW%29......now find L and W using equations 1 and 2
L=5W.........1.substitute in 2
L%2AW=450+cm%5E2 .....2
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5W%2AW=450+cm%5E2

5W%5E2=450+cm%5E2
W%5E2=450+cm%5E2%2F5
W%5E2=90+cm%5E2
W=sqrt%2890+cm%5E2%29
W=9.49cm.......now find L
L=5W
L=5%2A9.49cm
L=47.45cm
check the result:
A=L%2AW=450+cm%5E2
47.45cm%2A9.49cm=450+cm%5E2
450.3005cm%5E2=450+cm%5E2...round it
450cm%5E2=450+cm%5E2
plug these values in P:
P=2%28L%2BW%29
P=2%2847.45cm%2B9.49cm%29
P=2%2856.94cm%29
P=113.88cm