The coordinates of quadrilateral ABCD are A (-1, -5), B (8 ,2 ), C (11, 13) and D (2, 6). Using coordinate geometry, prove that quadrilateral ABCD is a rhombus.

Question

 please help me 

Answer 1

One way to prove that ABCD is a rhombus is to prove that its diagonals are perpendicular.

 

Show that the slope of AC is the negative reciprocal of BD!