A square and a rectangle have the same perimeter if the length and breadth of a rectangle are 25 cm and 15 cm respectively. Find the side of the square.

Given:

Length of rectangle = 25 cm  

Breadth of rectangle = 15 cm

To find:

Find the side of the square

Solution:

Perimeter of rectangle = 2 (length $+$ breadth)

                                          =  2 (25 $+$ 15)

                                         =  2 (40)

Perimeter of rectangle = 80 cm

Perimeter of rectangle = Perimeter of square

So, 

Perimeter of square = 80 cm

Let's take side of square as 'a'

Perimeter of square = 4 a

4 a  =  80

a = $\frac{80}{4}$  =  20

Therefore the side of square = 20 cm.