aphere inscribed into pyramid, with parallelogram base
Source: 2005 Oral Moscow Geometry Olympiad grades 10-11 p4
October 21, 2020
geometryparallelogrampyramidsphere
Problem Statement
A sphere can be inscribed into a pyramid, the base of which is a parallelogram. Prove that the sums of the areas of its opposite side faces are equal.(M. Volchkevich)