## Quick Reference

(between vectors)

Given vectors **a** and **b**, let and be directed line-segments representing **a** and **b**. Then the angle *θ* between the vectors **a** and **b** is the angle ∠*AOB*, where *θ* is taken to satisfy 0≤*θ*≤*π* (*θ* in radians), or 0≤*θ*≤180 (*θ* in degrees). It is given by

*Subjects:*
Mathematics — Dentistry.