The area of a triangle with vertices (0,0),(x1,y1),(x2,y2)(0,0), (x_1, y_1), (x_2, y_2)(0,0),(x1,y1),(x2,y2) is given by:
12∣x1y2−x2y1∣\frac{1}{2}|x_1y_2 - x_2y_1|21∣x1y2−x2y1∣
12(x1y1+x2y2)\frac{1}{2}(x_1y_1 + x_2y_2)21(x1y1+x2y2)
∣x1y2+x2y1∣|x_1y_2 + x_2y_1|∣x1y2+x2y1∣
x12+y12⋅x22+y22\sqrt{x_1^2 + y_1^2} \cdot \sqrt{x_2^2 + y_2^2}x12+y12⋅x22+y22