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:
0.5∣x1y2−x2y1∣0.5 |x_1y_2 - x_2y_1|0.5∣x1y2−x2y1∣
0.5∣x1y1−x2y2∣0.5 |x_1y_1 - x_2y_2|0.5∣x1y1−x2y2∣
x1y2+x2y1x_1y_2 + x_2y_1x1y2+x2y1
sqrtx12+y12timessqrtx22+y22\\sqrt{x_1^2+y_1^2} \\times \\sqrt{x_2^2+y_2^2}sqrtx12+y12timessqrtx22+y22