Isosceles, maybe?
Geometry
Level
pending
AB is equal to the radius.
∠CAO=20°
Then ∠COD=?
The answer is 60.
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1 solution
Join OB.
In triangle ABO
AB=OB (radius of circle)
Therefore, ∠BAO=∠BOA=20°
Now, ∠ABO= 180-40= 140°
In triangle OBC
∠OBC= 180-140= 40°
∠OCB=∠OBC= 40° (Since, OB=OC)
Therefore, ∠COB= 180-80= 100°
∠COD= 180-(100+20)= 60°