Do the three points (1,2,0), (−2,1,1), and (0,3,−1) form a right triangle?

Question

I think they do by using dot product.
Do the three points (1,1,1)(1,1,1), (2,3,2)(2,3,2), and (5,0,−1)(5,0,−1) form a right triangle?
I think they don't.

Answer 1

you are correct.