# Bisectors of angles A, B and C of a ∆ABC intersect its circumcircle at D, E and F

Bisectors of angles A, B and C of a ∆ABC intersect its circumcircle at D, E and F, respectively. Prove that the angles of the ∆DEF are 90° – \frac { 1 }{ 2 } A, 90° – \frac { 1 }{ 2 } B and 90° – \frac { 1 }{ 2 } C.