Question

A rectangle has an area of 20 cm².if length is decreased 2.5 cm

width is increased by 3 cm, the new figure is square , find perimeter
of the square ?

Answer 1

22cm

Explanation:

Start by writing down what you know:

Area of rectangle = length x width = L · W = 20

Since decreasing the length by 2.5 and increasing the width by 3 results in a square, we also know: L - 2.5 = W + 3

Solve the above for L: L = W+5.5

Substitute W+5.5 in for L in A = (W+5.5)·W = 20

Distribute on the left, subtract 20 from both sides, and solve the resulting quadratic. NOTE: Remember that we're dealing in length, so only the positive solution counts!

One side of the square = either W+3 or L-2.5, and perimeter of a square is 4s.