MathDB
rs geometry

Source: RS2004

March 20, 2005
geometryincentercircumcirclegeometry proposed

Problem Statement

Given an isosceles triangle ABCABC with base ABAB, cirumcenter OO, incenter SS and ∠C<60∘\angle C<60^\circ. The circumcircle of AOSAOS intersects ACAC at DD. Prove that SD∥BCSD\parallel BC and AS⊥ODAS\perp OD.
Back to ProblemsView on AoPS