Triangle their internal angles, measured here in degrees. A triangle that has two angles with the same measure also has two sides with the same length, and therefore it is an isosceles triangle. It follows that in a triangle where all angles have the same measure, all three sides have the same length, and such a triangle is therefore equilateral. Triangles are assumed to be two-dimensional plane figures, unless the context provides otherwise (see Non-planar triangles, below). In rigorous treatments, a triangle is therefore called a "2-simplex" (see also Polytope). Elementary facts about triangles were presented by Euclid in books 1–4
The Three Degrees Kenny Gamble and Leon Huff, where they had their greatest successes. The first song they recorded for the label was with the studio band MFSB, titled "TSOP (The Sound of Philadelphia)", which was the theme song for "Soul Train". In October 1973, the group also made an appearance on the American television sitcom "Sanford and Son" (season 3, episode 4), singing their song "I Didn't Know". Their first album for the Philadelphia International label, "The Three Degrees", spawned three hits: "Dirty Ol' Man" (which went gold in the Netherlands and Belgium), "Year Of Decision" (which made it to #13 in