Decide whether each statement is always true, sometimes true, or never true.
a. A cube is a polyhedron.
b. A polyhedron is a cube.
c. A right rectangular prism is a cube.
d. A cube is a right rectangular prism.
e. A regular polyhedron is a prism.
f. A prism is a regular polyhedron.
g. The diagonals of every face of a cube are the same length.
h. The diagonals of every face of a right rectangular prism are the same length.
i. A pyramid is a regular polyhedron.
j. A regular polyhedron is a pyramid.
k. A hexahedron is a cube.
l. A cube is a hexahedron.
