Recently I published a math problem Problem, today I will give you the solution.
if the area of a rectangle is reduced to its 4th part, its sides are divided in half
As the perimeter is 20, and perimeter is P = 2h + 2b where h: height and b: base.
Assuming that h = 6 and b = 4; P = 2 (6) + 2 (4) = 20
For a 4th part of area and knowing that each side is at the same P = 2 (h / 2) + 2 (b / 2). Then P = 2 (6/2) + 2 (4/2)
P = 10 cm. This applies to any measurement in which the perimeter is 20 cm