MathDB

3

Part of 2013 South africa National Olympiad

Problems(1)

SAMO 2013 Senior Round 3 Problem 3 - Tangent to Circumcircle

Source:

9/17/2013
Let ABC be an acute-angled triangle and AD one of its altitudes (D on BC). The line through D parallel to AB is denoted by ll, and t is the tangent to the circumcircle of ABC at A. Finally, let E be the intersection of ll and t. Show that CE and t are perpendicular to each other.
geometrycircumcircle