Squares are called squares
because they have equal length sides.
The perimeter of the square is the sum of the lengths of
the sides. And since all the sides are equal, this is just
four times the length of one side.
Perimeter of a square = s + s + s + s = 4s
The area of a square is the length of one side multiplied
by the length of another. But since these are the same, it
is also s².
Area of a square = s × s = s²
(Now do you see why they are called squares?)