Proof of Inscribed Angle Property
- Author:
- Julia
Because the sum of all the interior angles of a quadrilateral is 360°, central ∠=σ=ε+ζ +δ+ν
But ∆OBC and ∆OCD are isosceles triangles.
Therefore, ε=ζ and δ=ν
Therefore, inscribed ∠= ζ+ δ= 1/2 * σ =1/2 * (central ∠)