Answer:
x = 12
Step-by-step explanation:
x = length of side of square A
'x-3' represents length of side of square B
Perimeter of square A = 4x
Perimeter of square A = 4x - 12
we can set up the following proportion based on ratio of 4:3
4x / 4 = 4x - 12 / 3
cross-multiply:
4(3x) = 4(4x-12)
12x = 16x - 48
-4x = -48
x = 12