1. Answer – Always
The diagonals of a rhombus are always perpendicular. In fact, if the diagonals of a parallelogram are perpendicular bisectors of each other, then it must be a rhombus. In addition to this, a rhombus always has all four congruent sides.
2. Answer – Always
The diagonals of a rectangle are always congruent (i.e. they are equal in length). Furthermore, in every rectangle, the diagonals bisect each other. Because the diagonals are equal in length, each diagonal divides the rectangle into two congruent right triangles.
3. Answer – Never
The diagonals of a trapezoid are never perpendicular; the diagonals are only perpendicular in rhombuses and squares. In a trapezoid however, the diagonals are congruent. A trapezoid is a quadrilateral that has only one pair of parallel sides.
