# Quadrilateral problems on the coordinate plane

Challenge problems involving the coordinates of the vertices of the quadrilaterals.

### Problem

Rectangle A, B, C, D is graphed in the coordinate plane. The following are the vertices of the rectangle: A, left parenthesis, 2, comma, 1, right parenthesis, B, left parenthesis, 5, comma, 1, right parenthesis, C, left parenthesis, 5, comma, 6, right parenthesis, and D, left parenthesis, 2, comma, 6, right parenthesis.
Given these coordinates, what is the length of side A, B of this rectangle?
units