3

Part of 1988 IMO Shortlist

Problems(1)

Interior bisectors of the angles A,B and C

Source: IMO ShortList 1988, Problem 3, Canada 1, Problem 4 of ILL

ABC

is inscribed in a circle. The interior bisectors of the angles

A,B

C

meet the circle again at

A', B'

C'

respectively. Prove that the area of triangle

A'B'C'

is greater than or equal to the area of triangle

ABC.

geometrycircumcircletrigonometryinradiusgeometric inequalityIMO Shortlist