MathDB

incircle

Source: Austria 1988

July 8, 2009

geometryincentergeometric transformationreflectioncircumcirclegeometry proposed

Problem Statement

The bisectors of angles

B

and

C

of triangle

ABC

intersect the opposite sides in points

B'

and

C'

respectively. Show that the line

B'C'

intersects the incircle of the triangle.