- Walch Education
A square is a quadrilateral with two pairs of parallel opposite sides, consecutive sides that are perpendicular, and all sides congruent, meaning they have the same length. Quadrilateral ABCD has vertices A (–1, 2), B (1, 5), C (4, 3), and D (2, 0). Determine if this quadrilateral is a square. Note: Drag the blue points to try different figures.
- Plot the quadrilateral on a coordinate plane.
- First show the figure has two pairs of parallel opposite sides. Calculate the slope of each side using the general slope formula.
- Observe the slopes of each side.
- Show that the quadrilateral has four congruent sides.
- Make connections.