The quadrilateral formed by joining the midpoints of the sides of a quadrilateral ABCD, taken in order, is a rhombus, if
(a) ABCD is a parallelogram
(b) ABCD is a rhombus
(c) diagonals of ABCD are equal
(d) diagonals of ABCD are perpendicular to each other
The quadrilateral ABCD is a rhombus.
So, the sides AB, BC, CD and AD are equal.
Now, in ∆PQS, we have
(Using mid-point theorem)-----(1)
Similarly, in ∆PSR,
As, BC = DC
⇒1/2QS = 1/2PR
[From (1) and (2)]
So, QS = PR
Thus, the diagonals of PQRS are equal.
Hence, the correct option is (c).