Answer:
40.5in
Step-by-step explanation:
Given data
Let the width be x
L= 3x-15
Perimeter= 178cm
We know that
P=2L+2W
substitute
178= 2(3x-15)+2x
open bracket
178=6x-30+2x
collect like terms
178=8x-30
178-30= 8x
148= 8x
divide both sides by 8
x= 148/8
x=18.5 in
but L= 3x-15
L= 3*18.5-15
L=55.5-15
L=40.5 in
Hence the length is 40.5in
