Assertion: polyhedron's vertex | /r/HasProperty | seen at angle
Facets:
value: from the center
type: LOCATION
value: in such a regular tetrahedron
type: OTHER
Source sentences:
text: In such a regular tetrahedron, two vertices are seen from the center at an angle known as the tetrahedral angle (which is very familiar to chemists) whose cosine is -1/3 and whose value is 109.47122°...