Question

A square and a rectangle are isoperimetric and have a perimeter of 80 cm. knowing that the height of the rectangle exceeds the bases of 12 cm, calculates the area of ​​each figure.

[364cm2; 400cm2]

Answer 1

each side of the square would be 80/4 = 20 cm. so its area = 20^2 = 400 cm^2.
Th rectangle will have perimeter = 80 = 2x + 2(x - 12) where x = height of the rectangle
4x = 80+24 = 104
so x = 26
area of rectangle = 26*(26-12) = 364 cm^2

Answer 2

Square

(80:4)² =
20²=
400 cm² (area)

Rectangle

80:2=40cm (b+h)
40-12=28cm
28:2=14cm (b)
14+12=26cm (h)
A = b*h
14*26= 364 cm² (area)