Question

Is it true that "With any rhombus, the diagonals always cross at 90 degree angles."? If it is true can someone explain why?

Answer 1

Try breaking it into the four separate right triangles and look at them.

Answer 2

I look at them, but is there a theory or postulate of some sort involved?

Answer 3

it is true and its because all sides are equal in length... or adjacent sides are equal in length.

The only quadrilaterals where this occurs is in a square or kite

Answer 4

I see! Thank you very much :)