Given : ABCD is a rhombus. AB produced to E and F such that AE = AB = BF
Construction : Join ED and CF and produce it to meet at G.
To : ED⟂FCprove
Proof : AB is produced to points E and F such that.
AE = AB = BF .....(i)
Also, since ABCD is a rhombus
AB = CD = BC = AD ...(ii)
Now, in ΔBCF, BC = BF [From (i) and (ii)]
[∠4 and ∠3 are consecutive interior angles]
Hence proved.