Thread: Direction of a line segment relative to another

Consider three two-dimensional points a, b, and c. If we look at the angle formed by the line segment from a to b and the line segment from b to c, it either turns left, turns right, or forms a straight line.

What's the simplest way of solving this? Thanks.

What does "turns left, turns right" mean?
Does it mean the angle is acute, right, or obtuse?
Strictly speaking there is another option it could be a ray.

Originally Posted by Plato

What does "turns left, turns right" mean?
Does it mean the angle is acute, right, or obtuse?
Strictly speaking there is another option it could be a ray.

I assume so. This is an (IMHO poorly judged) exercise from a programming book.