Arbitrary Triangle Calculator
A closed figure (including its internal area) formed by three non-collinear points on a plane and the line segments connecting each two points is called a triangle. Each line segment that makes up a triangle is called a side of the triangle. The common endpoints of two adjacent sides are called vertices of the triangle. The angle between two adjacent sides is called the interior angle of the triangle, or simply the angle of the triangle. The angle between the extension of one side of the triangle and its adjacent side is called the exterior angle of the triangle. A triangle with A, B, and C as vertices is written as: △ABC, and is read as: triangle ABC.
The figure formed by three straight lines on a plane or three arcs on a sphere is called a plane triangle; the figure formed by three arcs is called a spherical triangle, also called a trilateral. △ABC..