1. **Convert degrees to radians** The formula to convert degrees to radians is: $$\text{radians} = \text{degrees} \times \frac{\pi}{180}$$ (a) For 300°: $$300 \times \frac{\pi}{180} = \frac{300\pi}{180} = \frac{5\pi}{3}$$ (b) For -18°: $$-18 \times \frac{\pi}{180} = \frac{-18\pi}{180} = -\frac{\pi}{10}$$ 2. **Convert radians to degrees** The formula to convert radians to degrees is: $$\text{degrees} = \text{radians} \times \frac{180}{\pi}$$ (a) For $\frac{5\pi}{6}$: $$\frac{5\pi}{6} \times \frac{180}{\pi} = \frac{5 \times 180}{6} = 150^\circ$$ (b) For 2 radians: $$2 \times \frac{180}{\pi} = \frac{360}{\pi} \approx 114.59^\circ$$ **Summary:** - 300° = $\frac{5\pi}{3}$ radians - -18° = $-\frac{\pi}{10}$ radians - $\frac{5\pi}{6}$ radians = 150° - 2 radians $\approx$ 114.59° The graph description shows the relationship between arc length $s$, radius $r$, and central angle $\theta$ in radians: $$s = r\theta \quad \text{and} \quad \theta = \frac{s}{r}$$ This means the angle in radians is the arc length divided by the radius.