37Volume via scalar triple product
Find the volume of the parallelepiped spanned by (1, 0, 0), (0, 2, 0) and (1, 1, 3).
Volume is the absolute value of the determinant of the matrix with the three vectors as rows. Expanding along the first row gives det = 1·(2·3−0·1) = 6, so the volume is 6.