In Figure, , AB = DE, and AC = DF. Prove that and BC = EF.
Solution.
Given: and
Also, AB = DE and AC = DF
To prove: and BC = EF
Proof: and AB = DE
and AC = DF
In ACFD quadrilateral
and AC = FD …..(1)
Thus ACFD is a parallelogram
and AD = CF …..(2)
In ABED quadrilateral
and AB = DE …..(3)
Thus ABED is a parallelogram
and AD = BE …..(4)
From equation 2 and 4
AD = BE = CF and …..(5)
In quadrilateral BCFE, BE = CF and {from equation 5}
So, BCFE is a parallelogram BC = EF and
Hence Proved.