\begin{definition}[Definition:Conjugate Angles]
The '''conjugate''' of an angle $\theta$ is the angle $\phi$ such that:
:$\theta + \phi = 2 \pi$
where $\theta$ and $\pi$ are expressed in radians.
That is, it is the angle that makes the given angle equal to a full angle.
Equivalently, the '''conjugate''' of an angle $\theta$ is the angle $\phi$ such that:
:$\theta + \phi = 360 \degrees$
where $\theta$ and $\pi$ are expressed in degrees.
Thus, '''conjugate angles''' are two angles whose measures add up to the measure of $4$ right angles.
That is, their measurements add up to $360$ degrees or $2 \pi$ radians.
\end{definition}