Question

Perimeter of a square with an area of 81cm2

Answer 1

If it's a square, both sides are equal, and both sides must times together to get 81 :)
The square root of 81 is 9.
9 times four ( for the four sides) gives you 37cm^2 ;)

Answer 2

$a^2=81|\sqrt{81}$
a=9
Perimeter:
4*a=4*9=36cm