MathDB

37

Part of 1992 IMO Longlists

Problems(1)

Prove that A+B+C < pi

Source:

9/2/2010
Let the circles C1,C2C_1, C_2, and C3C_3 be orthogonal to the circle CC and intersect each other inside CC forming acute angles of measures A,BA, B, and CC. Show that A+B+C<π.A + B +C < \pi.
geometrycirclesTrigonometric inequalityanglesIMO ShortlistIMO Longlist