Answer:
Length = 60 inches
Width = 17 inches
Explanation:
Let width = w
Length = 3w + 9
Perimeter = 154
Perimeter = 2(length + width)
2(3w + 9 + w) = 154
8w + 18 = 154
8w = 154 - 18
8w = 136
w = 136/8
w = 17 inches
Length = 3w + 9 = 3(17) + 9 = 60 inches