The sides AB and CD of a parallelogram ABCD are bisected at E and F. Prove that EBFD is a parallelogram.
Given: In ||gm ABCD, E and F are the midpoints of the side AB and CD respectively.
DE and BF are joined.
To prove : EBFD is a ||gm.
Construction: Join EF.
Proof : ∵ ABCD is a ||gm
∴ AB = CD and AB || CD
(Opposite sides of a ||gm are equal and parallel)
∴ EB || DF
and EB = DF
(∵ E and F are mid points of AB and CD)
∴ EBFD is a || gm.