how is the perimeter of a square sandbox with an area of 361 sq. ft. equal to 76

Question

i'm not understanding how they got 76 as the perimeter

Answer 1

First let x=the side length of the sandbox.  Since the sandbox is a square, the area of the square is x².  The perimeter of the square is 4x.  The problem says that the area of the sandbox is 361 sq. ft.  so you can write the equation  x²=361.  When you solve for x, take the square roots of both sides, you get 19.  So the side length of the sandbox is 19 ft.   Use this to find the perimeter 4(19)= perimeter.  The perimeter is then 76 ft.