Which of the following is not a property of a rectangle?
Diagonals are perpendicular
Opposite sides are congruent and parallel
Congruent diagonals.
4 right angles

Question

Which of the following is not a property of a rectangle? 
        Diagonals are perpendicular
         Opposite sides are congruent and parallel
         Congruent diagonals. 
         4 right angles

anonymous · Answer

The first one is not a property of a rectangle. Consider a long, thin rectangle. Imagine its diagonals.

+---+
|\    /|
| \  / |
|  \/  |
|  /\  |
| /  \ |
|/    \|
+---+

It is pretty clear just by inspection that the diagonals are not perpendicular (i.e., at right angles).

All the other statements are true of rectangles.