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
Pipeclay triangle Pipeclay triangle A pipeclay triangle is a piece of laboratory apparatus that is used to support a crucible being heated by a Bunsen burner or other heat source. It is made of wires strung in an equilateral triangle on which are strung hollow ceramic, normally fire clay, tubes. The triangle is usually supported on a tripod or iron ring. Unlike wire gauze, which primarily supports glassware such as beakers, flasks, or evaporating dishes and provides indirect heat transfer to the glassware, the pipeclay triangle normally supports a crucible and allows the flame to heat the crucible directly. The triangular shape