I want to find the area of a right triangle with vertices P,Q,R.

P (1,-1,2)

Q (0,3,4)

R (6,1,8)

Area of right triangle is |PQ x PR| / 2

vector PQ (-1,4,2)

vector PR (5,2,6)

cross product vector PQ and vector PR (20,-16,-22)

The area should be |20^2 + -16^2 + -22^2| / 2

= square root (20^2 + -16^2 + -22^2) / 2

= 570

I think I got this, I'm just doubting the formula. I have trouble knowing when |...| means what if it's absolute value or the square root.