main/src/georegression/metric/Area2D_F64.java
public static double triangle( Point2D_F64 a, Point2D_F64 b, Point2D_F64  c ) {
		double inner = a.x*(b.y - c.y) + b.x*(c.y - a.y) + c.x*(a.y - b.y);

		return Math.abs(inner/2.0);
	}
public static double triangle( Point2D_F64 a, Point2D_F64 b, Point2D_F64  c ) {
		double inner = a.x*(b.y - c.y) + b.x*(c.y - a.y) + c.x*(a.y - b.y);

		return Math.abs(inner/2.0);
	}
public static double triangle ( Point2D_F64 a , Point2D_F64 b , Point2D_F64 c ) { double inner = a . x * ( b . y - c . y ) + b . x * ( c . y - a . y ) + c . x * ( a . y - b . y ) ; return Math . abs ( inner / 2.0 ) ; }
Computes the area of an arbitrary triangle from 3-vertices.

area = | a.x*(b.y - c.y) + b.x*(c.y - a.y) + c.x*(a.y - b.y) | / 2

@param a Corner point 1
@param b Corner point 2
@param c Corner point 3
@return area
Computes the area of an arbitrary triangle from 3 - vertices .