A rectangle and a square have the same perimeters, what is the area of the square if the sides of the rectangle are 4cm and 14cm?

Let’s denote: a – side of a square, b = 4cm and c = 14cm – sides of a rectangle
The perimeter of a rectangle is equal to the sum of the lengths of all its sides:
P = 2 * (b + c) = 2 * (4cm + 14cm) = 36cm
Since all sides of the square are equal, the side of the square is a = P / 4 = 36cm / 4 = 9cm
Square area:
S = a ^ 2 = (9cm) ^ 2 = 81cm ^ 2