Question

The area of a square is 81cm. Find its perimeter OK

Answer 1

Given: Area of a square = 81 cm²

=> side² = 81

=> side = √81 = 9cm

So, perimeter = 4 × side

=> 4 × 9 cm

=> 36cm

Answer 2

The required perimeter is 36 cm

Step-by-step explanation:

We know that, if a units be the length of a side of a square, then

its perimeter = 4a units

& area = a² unit²

Given that, the area of the square is 81 cm²

Then if a cm be the length of each side, we have

a² = 81

or, a² = 9²

i.e., a = 9

Thus each side of the square is 9 cm

Therefore the perimeter of the square is

= 4a = 4 * 9 cm = 36 cm