Answer:
width = 16 in.; length = 20 in.
Explanation:
The formula for perimeter, P, of a rectangle is
P = 2l + 2w, where l is the length and w is the width.
Since we're told that the length is 4 in. longer than the width, we know that
l = w + 4
We can substitute w +4 for l in the perimeter equation and plug in 72 for P. This will allow us to first find the width:
72 = 2(w + 4) + 2w
72 = 2w + 8 + 2w
72 = 4w + 8
64 = 4w
16 in. = w
The width is 16 and since 4 more than 16 is 20, the length is 20 inches.
Now, we can check if when we plug in 72 for P, 16 for w, and 20 for l, we get 72:
72 = 2(16) + 2(20)
72 = 32 + 40
72 = 72
Therefore, our answers are correct