MMO 012 Moscow MO 1935 unfolding lateral surface of cone, angle wanted
Source:
July 17, 2019
geometry3D geometryconepyramidangles
Problem Statement
The unfolding of the lateral surface of a cone is a sector of angle . The angles at the base of a pyramid constitute an arithmetic progression with a difference of . The pyramid is inscribed in the cone. Consider a lateral face of the pyramid with the smallest area. Find the angle between the plane of this face and the base.