Answer: Use the slope formula to prove that four right angles exist as a result of perpendicular sides.
Explanation:
To be classified as a square, a quadrilateral must have 2 pairs of parallel sides, 4 sides equal in length, and 4 right angles. By using the slope formula, it can be determined whether the quadrilateral's sides are perpendicular. If so, 4 right angles exist and the shape is a square. If not, the shape is not a square.