1. Express the angle in radian measure as a multiple of $\pi$ radians. Recall that $180^\circ = \pi$ radians. (a) $30^\circ = \frac{30}{180} \pi = \frac{1}{6} \pi$ (b) $60^\circ = \frac{60}{180} \pi = \frac{1}{3} \pi$ (c) $180^\circ = \pi$ (d) $225^\circ = \frac{225}{180} \pi = \frac{5}{4} \pi$ (e) $720^\circ = \frac{720}{180} \pi = 4 \pi$ (f) $270^\circ = \frac{270}{180} \pi = \frac{3}{2} \pi$ 2. Solve for the value of the following angles in degrees. Recall that $1$ radian $= \frac{180}{\pi}$ degrees. (a) $3$ radians $= 3 \times \frac{180}{\pi} = \frac{540}{\pi} \approx 171.89^\circ$ (b) $1.5$ radians $= 1.5 \times \frac{180}{\pi} = \frac{270}{\pi} \approx 85.94^\circ$ (c) $4.32$ radians $= 4.32 \times \frac{180}{\pi} = \frac{777.6}{\pi} \approx 248.01^\circ$ 3. Find the radius of a circle if its circumference is 360 cm. Recall circumference formula: $C = 2 \pi r$ Given $C = 360$, solve for $r$: $$r = \frac{C}{2 \pi} = \frac{360}{2 \pi} = \frac{180}{\pi} \approx 57.30 \text{ cm}$$ \boxed{\text{Radius } r \approx 57.30 \text{ cm}}