Sides of Triangle Theorem Small 320×205 Medium 640×411 Large 1024×657 Download TIFF Original 2400×1540 | (136.3 KB) Description Illustration used to prove that "The sum of any two sides of a triangle is greater than the third side." Keywords angles, geometry, proof, prove, Sides, theorem, theorems, triangle, triangles Galleries Geometric Theorems and Proofs Source: C. A. Hart & Daniel D. Feldman Plane And Solid Geometry (New York: American Book Company, 1911) 59