Question

In figure, it is given that O is the centre of the circle and ∠AOC = 150°. Find ∠ABC.

Answer 1

∠AOC = 150° (Given) 

By degree measure theorem: ∠ABC = (reflex∠AOC)/2 …(1) 

We know, ∠AOC + reflex(∠AOC) = 360° [Complex angle] 

150° + reflex∠AOC = 360° 

or reflex ∠AOC = 360° −150° = 210° 

From (1) => ∠ABC = 210°/2 = 105°