MathDB
N satisfies ∠ NBA =∠ BAM and ∠ NCA = ∠ CAM

Source: Romanian TST 2000

February 18, 2011
geometrycircumcirclegeometry proposed

Problem Statement

Let ABCABC be an acute-angled triangle and MM be the midpoint of the side BCBC. Let NN be a point in the interior of the triangle ABCABC such that NBA=BAM\angle NBA=\angle BAM and NCA=CAM\angle NCA=\angle CAM. Prove that NAB=MAC\angle NAB=\angle MAC.
Gabriel Nagy