Provide the reference angle in the same units as the original (degrees stay in degrees, radians stay in radians):

[tex]\[
\begin{tabular}{|c|c|c|}
\hline
Angle $\theta$ & Quadrant & Reference Angle $\bar{\theta}$ \\
\hline
$135^{\circ}$ & 2 & $45^{\circ}$ \\
\hline
$255^{\circ}$ & 3 & $75^{\circ}$ \\
\hline
$\frac{\pi}{3}$ & 1 & $\frac{\pi}{3}$ \\
\hline
$\frac{16 \pi}{9}$ & 2 & $\frac{7 \pi}{9}$ \\
\hline
\end{tabular}
\][/tex]



Answer :

Let's solve for the equivalent angle, its quadrant, and the reference angle for [tex]\(\frac{16 \pi}{9}\)[/tex].

1. Finding the Equivalent Angle Between [tex]\(0\)[/tex] and [tex]\(2\pi\)[/tex]:

The given angle is [tex]\(\theta = \frac{16 \pi}{9}\)[/tex].

To find the equivalent angle, we need to subtract multiples of [tex]\(2\pi\)[/tex] (because [tex]\(\theta = \theta + 2\pi k\)[/tex] for any integer [tex]\(k\)[/tex]).

[tex]\[ \text{Equivalent}\ \theta = \frac{16 \pi}{9} \mod 2 \pi \][/tex]

The equivalent angle (taking modulus) is approximately [tex]\(5.585\)[/tex] radians.

2. Determine the Quadrant of the Equivalent Angle:

- [tex]\(0 \leq \theta < \frac{\pi}{2}\)[/tex]: Quadrant 1
- [tex]\(\frac{\pi}{2} \leq \theta < \pi\)[/tex]: Quadrant 2
- [tex]\(\pi \leq \theta < \frac{3\pi}{2}\)[/tex]: Quadrant 3
- [tex]\(\frac{3\pi}{2} \leq \theta < 2\pi\)[/tex]: Quadrant 4

Since [tex]\(5.585 \; \text{radians}\)[/tex] is between [tex]\(\frac{3\pi}{2}\)[/tex] (which is approximately 4.712) and [tex]\(2\pi\)[/tex] (which is approximately 6.283), the angle is in Quadrant 4.

3. Calculate the Reference Angle:

The reference angle [tex]\(\bar{\theta}\)[/tex] is the acute angle formed with the closest x-axis.

For angles in Quadrant 4, the reference angle [tex]\(\bar{\theta}\)[/tex] can be found by:
[tex]\[ \bar{\theta} = 2\pi - \theta \][/tex]
Substituting our equivalent angle:
[tex]\[ \bar{\theta} = 2\pi - 5.585 \][/tex]
The reference angle is approximately [tex]\(0.698 \; \text{radians}\)[/tex].

Summarizing this information in our table, we get:
[tex]\[ \begin{array}{|c|c|c|} \hline \text{Angle } \theta & \text{Quadrant} & \text{Reference Angle } \bar{\theta} \\ \hline 135^{\circ} & 2 & 45^{\circ} \\ \hline 255^{\circ} & 3 & 75^{\circ} \\ \hline \frac{\pi}{3} & 1 & 60^{\circ} \\ \hline \frac{16\pi}{9} & 4 & 0.698 \; \text{radians} \\ \hline \end{array} \][/tex]

The angle [tex]\(\frac{16 \pi}{9}\)[/tex] is in Quadrant 4 with a reference angle of approximately 0.698 radians.