Given that two sides of a parallelogram are in the ratio 5:3 so let x as common multiple.
Also given that its perimeter is 64cm
But we know that perimeter = 2 (length + width) = 2(5x + 3x)
64 = 2(5x + 3x)
64 = 2(8x)
64 = 16x
x = 64/16 = 4
5x=20
3x=12
Therefore the sides are 20 and 12