Explanation:
you know what a square is ?
it is a closed shape with 4 sides.
all 4 sides are equally long.
all 4 inner angle are 90 degrees.
you know what a perimeter is ?
it is the circumference, the whole way one time around the shape, around the outline of a given structure.
if you don't know the terms, for heaven's sake, please ask your teacher, your friends, your parents or us here directly.
don't wait. don't be afraid or ashamed.
because this here is an extremely simple problem to solve, once you understand the words used.
so, as per the explanations, the perimeter of a square is the sum of the lengths of all sides. and because all sides are equally long, this means the perimeter is simply 4 times the length of one side.
36 = 4×side
side = 36/4 = 9cm
so, each side of the square is 9cm long.