Given the points A (1, 2, –1), B(0, 3, –2), and C(–2,6,0). Determine the area of ∆𝐴𝐵𝐶, to the nearest one decimal squared units.
calculate
u = B-A
v = C-A
Then the area is 1/2 u×v
oobleck meant to say
area = 1/2 | u×v | , that is, half the magnitude of u×v