Posted by sha on .
dimension of a floor; the perimeter of a rectangular floor is 90ft. find the dimensions of the floor if the length is twice the width

fintemath 
Ms. Sue,
P = 2L + 2W
90 = 4W + 2W
90 = 6W
15 = W
Check:
15 + 15 + 30 + 30 = 90 
fintemath 
sha,
i know 90 is the perimeter but where did the 4W + 2W come from?

finitemath 
Ms. Sue,
This is the formula for a perimeter.
P = 2L + 2W
Your problem states that the length is twice the width. Therefore, L = 2W 
fintemath 
sha,
what happened to 2L? sorry for my dumb question.

fintemath 
sha,
oh nevermind.. i got it. thanks for helping me Ms. Sue (:

fintemath 
Ms. Sue,
You're welcome, Sha.