In Fig. 6.63, D is a point on side BC of Δ ABC such thatProve that AD is thebisector of ∠ BAC
Construct a line CM which meets BA extended up to AM so that AM = AC
This means, ∠AMC = ∠ACM (Angles opposite to equal sides)
(Given)
BECAUSE AM = AC
Hence,
ΔABD ΔMBC
Hence, AD parallel MC
This means,
∠DAC = ∠ACM (Alternate angles)
Since,
∠AMC = ∠ACM
Hence,
∠DAC = ∠BDA
Hence, AD is the bisector of ∠BAC