## Detailed description

Cartesian plane. Solid line joining points *A*(*x*1,*y*1) and *B*(*x*2, *y*2). Dotted line from *A* to (*x*2, *y1*) labelled '*x*2 – *x*1' above 'run'; dotted line from *B *to (*x*2, *y1*) labelled '*y*2 *– y2*' above 'rise'. Right-angle symbol at point (*x*2, *y1*).