Two Equal Prisms Small 320×184 Medium 640×368 Large 1024×588 Download Tiff Original 2400×1379 | (308.5 KB) Description Diagram used to prove the theorem: "Two prisms are equal when the three faces about a trihedral of one are equal respectively to the three faces about a trihedral of the other, and similarly arranged." Keywords angle, congruent, equal, prism, prisms, trihedral angles, trihedrals Galleries Geometric Theorems and Proofs Source: Arthur Latham Baker The Elements of Solid Geometr with Numerous Exercises (Boston, MA: Ginn & Company, 1893)