Question

ABC is a triangle in which angleB = 2angleC. D is a point on BC such that AD bisects angleBAC and
AB = CD. Find 1/9 AngleBAC​

Answer 1

Triangle ABC and ADC are similar (two sides and one angle is equal)
So ∠ CAD = ∠ ACB = C
∠BAC = 2c
And in triangle ABC ∠BAC + ∠ABC + ∠ACB
= 2c+2c+c
= 5c
= 180c
= 180/5
= 36
∠BAC = 2c
= 2x36
= 72