1. ## prove rhombus

The coordinates of the vertices of parallelogram RMBS are R(–4, 5), M(1, 4), B(2, –1), and S(–3, 0). Using the diagonals, prove that RMBS is a rhombus. Show all your work and state appropriate formulas and theorems used.

Any help is appreciated.

2. ## Re: prove rhombus

Prove the diagonals are perpendicular. The product of the gradients of the diagonals should equal -1.