Question

If in a triangle ABC,line DE//BC intersects AB in D and AC in D,then prove​

Answer 1

Answer:

∠ABC=∠ACB

2

1

∠ABC=

2

1

∠ACB

∠ABO=∠ACO (I)

In △ABO and △ACO,

∠ABO=∠ACO (From I)

AO=AO (Common side)

AB=AC (Given)

Thus, △ABO≅△ACO (SAS rule)

hence, ∠OAB=∠OAC (By cpct)

Thus, OA bisects ∠A.

I hope you have understood this one !