A quadrilateral ABCD is drawn in which the mid points of sides AB, BC, CD and AD are P, Q, R and S respectively.
If quadrilateral ABCD is a parallelogram, what can be said about sides SP and QR?
Equal
Parallel
Join the diagonal BD of quadrilateral ABCD.
In ΔABD , SP || BD and SP = 12 BD (mid point theorem) ------- I
In ΔBCD , QR || BD and QR = 12 BD (mid point theorem) ------- II
From I and II, SP || QR and SP = QR -------- III
Thus, sides SP and QR are equal and parallel.