Knowing the area of a square 361 dm2, find: a) its side. b) its perimeter.

a) A square has all sides equal. The area of a square is equal to the square of its side a:
S = a ^ 2.
Knowing the area of a square, we find its side by making the equation:
a ^ 2 = 361;
a = √361;
a = 19.
The side of the square is 19 in.
b) The perimeter of a square is equal to its side multiplied by 4:
P = 4 • a.
Knowing the side of the square, we find its perimeter:
P = 4 • 19 = 76 (dm.).
Answer: the side of the square is 19 inches; the perimeter of the square is 76 dm.