Question

What is the angle between `<1,5,7 >` and `< 6,8,1 >`?

Answer 1

52.49 deg, nearly.

Explanation:

use the angle between two vectors is arc cos (cross product of the components) / (product of the lengths of the vectors).
Here, it is arc cos (6 + 40 + 7) / (`sqrt`75 `sqrt`101))