Problem 60. Isosceles triangle, Congruence, Angles. Level: High School, SAT Prep, College

In the figure below, ABC is an isosceles triangle (AB = BC),  mÐABD = 30 degrees, mÐDBC = 10 degrees, and AC = BD. Prove that: mÐDCB = 20 degrees. Post a comment or solution.

 

See Also:

Proposed Problem 61:
Triangle, Trisection of Sides, Perimeter.

Problem 59: Right and Equilateral Triangles, Midpoints..

Problem 58: Right Triangle, Congruence, Perpendiculars.