Length = 60; Width = 36
The formula for Perimeter is P = 2L + 2W
Where L = length; W = width
192 = 2L + 2W
= 2(5x) + 2(3x)
= 10x + 6x
= 16x
192/16 = 16x/16
x = 12
Substitute the values:
192 = 2(5x) + 2(3x)
= 2(5*12) + 2(3*12)
= 2(60) + 2(36)
192 = 192