Question

In the given figure, AB is a chord of a circle with centre O and AB is produced to C such that BC = OB. Also, CO is joined and produced to meet the circle in D. If ∠ACD = 25°, then ∠AOD=? 

a.50°
b.75°
c.90°
d.100°​

Answer 1

Answer:

△OBC, OB = BC

⇒ ∠BOC = ∠BCO = y ...[angles opp. to equal sides are equal]

∠OBA is the exterior angle of △BOC

So, ∠ABO = 2y ...[ext. angle is equal to the sum of int. opp. angles]

Similarly, ∠AOD is the exterior angle of △AOC

∴ x = 2y + y = 3y

Answer 2

answer is option b

75

seventy-five degree