SOLUTION: A rectangle's length is 3 times its width. Its area is 108 square cm. What are its dimensions.

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Question 279061: A rectangle's length is 3 times its width. Its area is 108 square cm. What are its dimensions.
Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
A+=+Area+of+rectangle
L+=+Length
W+=+Width
A+=+L+%2A+W
A+=+108
L+=+3W
.
108+=+L+%2A+W+=+3W+%2A+W+=+3W%5E2
W%5E2+=+108%2F3+=+36
W+=+sqrt%2836%29+=++6
.
The square root of 36 is either +6 or -6, BUT a negative width does not make sense, so we can start with w=6.
.
L+=+3W+=+3%2A6+=+18
.
Checking the A
18+%2A+6+=+108
OK.
.
Answer:
The rectangle's length is 18; the width is 6.
.
Done