How can you prove the converse of the diagonals of a rhombus are perpendicular.

The only converse that one could have would be this:

"If the diagonals of a parallelogram are perpendicular, the parallelogram is a rhombus." 

We would have to be given that it was a parallelogram.


Maybe you meant this instead:

The diagonals of a rhombus are perpendicular bisectors of each other.

Then the converse would be:

"If the diagonals of a quadrilateral are perpendicular bisectors of 
each other, the quadrilateral is a rhombus.

  

Repost and tell us which one it is, or if it is smoething else.
Then we'll prove it.

Edwin