Question

Prove that the points (−7, −3), (5, 10), (15, 8) and (3, −5) taken in order are the corners
of a parallelogram.

Answer 1

A(-7,-3) B(5,10) C(15,8) D(3,-5)

Slopes of  AB = 13/12       AD = -2/10 =-1/5        BC = -2/10 = -1/5
               CD = -13/-12 = 13/12
AB || CD    AD || BC

hence ABCD is a parallelogram