Home Geometry Problems All problems Visual Index Problems Art Gallery 511-520 Double Angle Solution / comment        By Antonio Gutierrez

Problem 513: Triangle, Double Angle, Exterior Angle Bisector, Measure.
Level: High School, College, SAT Prep.

The drawing shows a triangle ABC with the exterior angle bisector BD. The angle A is double the angle C. Prove that AD=AB+BC.

Triangle, Double angle, exterior angle bisector


Geometry problem solving is one of the most challenging skills for students to learn. When a problem requires auxiliary construction, the difficulty of the problem increases drastically, perhaps because deciding which construction to make is an ill-structured problem. By “construction,” we mean adding geometric figures (points, lines, planes) to a problem figure that wasn’t mentioned as "given."

  Recent Additions