The perimeter of a rectangular is P = 2L + 2W. Solve for L if the perimeter is 220 ft and the length is 10 ft more than the width.
Mathematics · High School · Tue Nov 03 2020
Answered on
Alright so we have the perimeter=2L+2W this is equal to 220 ft. A rectangular has 2 lengths and 2 widths. The trick in solving these kind of problems, is to eliminate unknown values. In this case we have 2 unknown values: L (length) and W (width).
What we can do here is express one of them, relation to the other unknown value. From the exercise we know that L=W+10 so length is 10ft more than the width.
That expression we can put it in the first equation for the perimeter, but instead of L we put W+10.
So,
P=2(W+10)+2W ==>P=2W+20+2W ===> P=4W+20 ==> 220-20=4W
===>4W=200
W=50ft
We know that L=W+10
so L=50+10=60ft