The external bisector of ∠ABC of ’ ABC intersects the straight line through A and parallel to BC at the point D. If ∠ABC = 50°, then measure of ∠ADB is ’ ABC ds ∠ABC

Answer : Option C

Explanation :

BD is external bisector of ∠ABC

∠ABC = 50°

AD || BC

∴ ∠DAB = 50°

∠ABE = 180° – 50° = 130°

∴ ∠DBA = 65°

∴ ∠ADB = 180° – 65° – 50° = 65°