The diagonals of a parallelogram are along the lines and . Then, must be a
- A.rectangle
- B.square
- C.cyclic quadrilateral
- D.rhombus
Show answer and solution
Correct option: D
Solution
The two diagonal lines have slopes -1/3 and 3. Their product is (-1/3)(3) = -1, so the diagonals are perpendicular. In a parallelogram, perpendicular diagonals is the condition for a rhombus. (A rectangle requires equal diagonals, not perpendicular ones.) Hence PQRS must be a rhombus.
[1998]