from an external point p, two tangents pa and pb are drawn to the circle c(o,r). if op=2r show that the triangle apb is equilateral.
AP is the tangent to the circle.
∴ OA ⊥ AP (Radius is perpendicular to the tangent at the point of contact)
⇒ ∠ OAP = 90º
In Δ OAP,