Assertion: tetrahedron's edge | /r/HasProperty | tangent
Facets:
value: to a sphere
type: LOCATION
Source sentences:
text: If all edges of a square pyramid (or any convex polyhedron) are tangent to a sphere so that the average position of the tangential points are at the center of the sphere, then the pyramid is said to be canonical, and it forms half of a regular octahedron.