IMO 1985 LL USS93
The sphere inscribed in tetrahedron ABCD touches the sides
IMO 1985 LL USS93
Origin: USS
Problem
The sphere inscribed in tetrahedron ABCD touches the sides ABD and DBC at points K and M, respectively. Prove that ∡AKB = ∡DMC.
The sphere inscribed in tetrahedron ABCD touches the sides
Origin: USS
The sphere inscribed in tetrahedron ABCD touches the sides ABD and DBC at points K and M, respectively. Prove that ∡AKB = ∡DMC.