given concurrent _|_ through incenters of pyramid 1991 Kyiv City MO 11.5
Source:
July 19, 2021
geometryincenterpyramid3D geometry
Problem Statement
Lines that are drawn perpendicular to the faces of a triangular pyramid through the centers of the inscribed circles intersect at one point. Prove that the sums of the opposite edges of such a pyramid are equal to each other.