In the given figure, O is the centre of a circle and ∠AOC = 130°. Then, ∠ABC = ?
Given: ∠AOC = 130°
Here,
(Exterior ∠AOC) = 360° – (interior ∠AOC)
(Exterior ∠AOC) = 360° – 130°
(Exterior ∠AOC) = 230°
We know that,
(Exterior ∠AOC) = 2 × ∠ABC
230° = 2 × ∠ABC
∠ABC = = 115°
∴ ∠ABC = 115°