T1R1I1H4E1D2R1A1L1
13 points
TRIHEDRAL is validvalid
[n TRIHEDRALS]
a solid having three sides or faces; thus, a trihedral angle is a solid angle bounded by three plane angles [n -S]
[n TRIHEDRALS]
a solid having three sides or faces; thus, a trihedral angle is a solid angle bounded by three plane angles [n -S]