Date: Jun 22, 2013 3:59 AM Author: clarice Subject: vertices of a parallelogram Show that the points (-1, -3), (-2,0), (1,6), (2,3) draw the vertices of a parallelogram. is the parallelogram a rectangle???

should i use the d^2=sqrt(X2-X1)+(Y2-Y1)

c^2= a^2 + b^2 ??? how since there are 4 points in there??? how can i use the pythagorean????