In a convex quadrilateral $ABCD, AC\perp BD, \angle BCA = 10^o,\angle BDA = 20^o, \angle BAC = 40^o$. Find $\angle BDC$.
Problem
Source: 2011 Oral Moscow Geometry Olympiad grades 10-11 p5
Tags: Angle Chasing, angles, perpendicular, geometry
Source: 2011 Oral Moscow Geometry Olympiad grades 10-11 p5
Tags: Angle Chasing, angles, perpendicular, geometry
In a convex quadrilateral $ABCD, AC\perp BD, \angle BCA = 10^o,\angle BDA = 20^o, \angle BAC = 40^o$. Find $\angle BDC$.