MathDB
Math Prize 2011 Problem 8

Source:

September 19, 2011
geometry

Problem Statement

In the figure below, points AA, BB, and CC are distance 6 from each other. Say that a point XX is reachable if there is a path (not necessarily straight) connecting AA and XX of length at most 8 that does not intersect the interior of BC\overline{BC}. (Both XX and the path must lie on the plane containing AA, BB, and CC.) Let RR be the set of reachable points. What is the area of RR? [asy] unitsize(40); pair A = dir(90); pair B = dir(210); pair C = dir(330); dot(A); dot(B); dot(C); draw(B -- C); label("AA", A, N); label("BB", B, W); label("CC", C, E); [/asy]