Use the converse rule that the diagonals of a rhombus bisect each other at 90 degrees and that when 2 lines bisect each other at 90 degrees the quadrilateral formed by joining the points is a rhombus to show:

that the points with co-ordinates (1,2) (8,-2) (7,6) (0,10) are the vertices of a rhombus, and find the area.

Any pointers?

I am thinking along the lines of proving that the angles in the middle are 90, but not sure how to go about it, I thought about using pythag but how would I find the length of the diagnonals?