MathDB
the sum of dihedral angles equals 2 pi (ILL 1982 - P50)

Source:

May 16, 2011
geometry

Problem Statement

Let OO be the midpoint of the axis of a right circular cylinder. Let AA and BB be diametrically opposite points of one base, and CC a point of the other base circle that does not belong to the plane OABOAB. Prove that the sum of dihedral angles of the trihedral OABCOABC is equal to 2π2\pi.
Back to ProblemsView on AoPS