Триъгълник: Разлика между версии

The brackets in the above formula are required in order to prevent numerical instability in the evaluation.

 

If any four of a triangle's elements (vertices, and/or elements of its sides) are [[Distance geometry#plane|plane]] to each other, the triangle is called ''plane''. Geometers also study non-planar triangles in noneuclidean geometries, such as [[spherical triangle]]s in [[spherical geometry]] and [[hyperbolic triangle]]s in [[hyperbolic geometry]].-->