Question

If the length of a diagonal of a square is 18, find the perimeter of the square.

Answer 1

The length of a diagonal of a square is the side*sqrt(2). Let's call one side of the square: s

So we have 18 = s*sqrt(2)

18/sqrt(2) = s

18sqrt(2)/2 = s

9sqrt(2) = s

Since the perimeter is 4 sides we multiply by 4 to get 36sqrt(2) as the perimeter.