A wire is in the shape of a rectangle. Its length is 40 cm, and its breadth is 20 cm. If the same wire is bent in the shape of a square, what will be the measure of each side?

We know that the perimeter of a rectangle = 2 (length + breadth)

The perimeter of a square = 4 × side of a square

According to the question, the perimeter of a rectangle = the perimeter of a square

2 (length + breadth) = 4 × side of a square

2 (40 + 20) = 4 × side of a square

2 × 60 = 4 × side of a square

Side of a square =$\frac{120}{4}$ = 30 cm

Therefore, each side of a square is 30 cm.