MathDB
Measure of angle CAB

Source: IMO ShortList 1990, Problem 9 (HUN 3)

August 15, 2008
geometryincentertrigonometryanglemidpointIMO Shortlist

Problem Statement

The incenter of the triangle ABC ABC is K. K. The midpoint of AB AB is C1 C_1 and that of AC AC is B1. B_1. The lines C1K C_1K and AC AC meet at B2, B_2, the lines B1K B_1K and AB AB at C2. C_2. If the areas of the triangles AB2C2 AB_2C_2 and ABC ABC are equal, what is the measure of angle ∠CAB? \angle CAB?
Back to ProblemsView on AoPS