MathDB

6

Part of 1979 Vietnam National Olympiad

Problems(1)

find 2 points in plane so that t4 points form a regular tetrahedron

Source: Vietnam MO 1979 P6

7/28/2018
ABCDABCD is a rectangle with BC/AB=2BC / AB = \sqrt2. ABEFABEF is a congruent rectangle in a different plane. Find the angle DAFDAF such that the lines CACA and BFBF are perpendicular. In this configuration, find two points on the line CACA and two points on the line BFBF so that the four points form a regular tetrahedron.
geometry3-Dimensional Geometryconstructiontetrahedron3D geometry