MENU: home page

unit of measure: the base unit | the supplementary unit | the derived unit

geometry: the area of a flat figure | the area of a solid | the volume of the solid

The area of a triangle

by the side and its adjacent angles


A triangle is a polygon formed by the union of three segments, where the points of intersection are non-collinear points. Points of intersection are called vertexes, and the segments are referred to as sides.

The scalene triangle is the triangle which has all sides of different lengths.

The area of a triangle, in case there are known a side and its adjacent angles, is equal to the semi-product of square of the known side and fraction, where the numerator is the product of sinuses of adjacent angles, and the denominator is the sine of opposite angle.

Computing relationship:


a — the side of triangle;

β, γ — — the angles adjacent to the side , in °.

Calculator: the area of a triangle

For separation of number integers and decimals, use the symbol – point [.]

the side of triangle — a

the angle adjacent to the side — a β


the angle adjacent to the side — a γ



the area of a triangle =



context information: contemporary and archaic unit of measurement of area