The diagnals of a parallelogram are congruent

Question

Special Triangles. Discovering Geometry, An Investigation Approach

Answer 1

If the diagonals (check spelling!) of a parallelogram are congruent, then that parallelogram must be a rectangle.

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

A square is a rhombus, but the converse of this statement is not necessarily true.