Answer
A Parallelogram with four right angles and all sides of equal length is called a square.
Work Step by Step
A Parallelogram is a special type of polygon with four sides with opposites sides parallel and is of equal length. Also, the opposite angles of a parallelogram are of equal measure.
In a parallelogram, if one angle is aright angle, then every other angle must be aright angle.
A parallelogram is classified according to the sides and measure of the angle.The parallelogram with all four angles at the right angle and all sides are equal in length, it is called a square. Square has opposite sides parallel. The diagonals of square intersect (bisect) each other.