Answer:
Width = 27
Length = 9
*You might of switched width and length around please check*
Explanation:
Width = 3x
Length = x
Perimeter Formula
2(3x+x) = 72
2(4x) = 72
8x = 72
x = 9
Since X was found, plug it in to find the width and length
3(9) = 27
x = 9