Answer
$\approx 0.78$
Work Step by Step
RECALL:
The following are the means on how to find the reference angle of an angle $\theta$ based on its position:
(1) Quadrant I: $\theta$ (itself)
(2) Quadrant II: $\pi-\theta$
(3) Quadrant III: $\theta - \pi$
(4) Quadrant IV: $2\pi-\theta$
The angle $\theta = 5.5$ is between $\frac{3\pi}{2}\approx 4.71$ and $2\pi \approx 6.28$. This means that the angle is in in Quadrant IV.
Use formula (4) to obtain:
reference angle of $5.5$ is $2\pi - 5.5 \approx 0.78$
