CCSS IP Math I 6.1.1 Example 5

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 [i]ABCD[/i] has vertices [i]A[/i] (–1, 2), [i]B[/i] (1, 5), [i]C[/i] (4, 3), and [i]D[/i] (2, 0). Determine if this quadrilateral is a square.

[list=1] [*]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. [/list]