The perimeter of anything is the distance all the way around it one time.
A square has 4 sides and they're all the same length.
So the perimeter is (4) x (the length of one side) .
Other things it's the same as:
-- (double the square's diagonal) x (the square root of 2)
-- (4) x (the square root of the square's area)
-- the shortest amount of fence you can use to enclose
a given amount of area inside a rectangle
