Find the Reference Angle -10pi

Add ${\displaystyle 2\pi }$ to ${\displaystyle -10\pi }$.

The resulting angle of ${\displaystyle -8\pi }$ is coterminal with ${\displaystyle -10\pi }$ but isn\'t positive. Repeat the step.

Add ${\displaystyle 2\pi }$ to ${\displaystyle -8\pi }$.

The resulting angle of ${\displaystyle -6\pi }$ is coterminal with ${\displaystyle -10\pi }$ but isn\'t positive. Repeat the step.

Add ${\displaystyle 2\pi }$ to ${\displaystyle -6\pi }$.

The resulting angle of ${\displaystyle -4\pi }$ is coterminal with ${\displaystyle -10\pi }$ but isn\'t positive. Repeat the step.

Add ${\displaystyle 2\pi }$ to ${\displaystyle -4\pi }$.

The resulting angle of ${\displaystyle -2\pi }$ is coterminal with ${\displaystyle -10\pi }$ but isn\'t positive. Repeat the step.

Add ${\displaystyle 2\pi }$ to ${\displaystyle -2\pi }$.

The resulting angle of ${\displaystyle 0}$ is positive and coterminal with ${\displaystyle -10\pi }$.