## Calculus (3rd Edition)

(a) $\dfrac{180}{\pi} \approx 57.3^{\circ}$ (b)$\, 60^{\circ}$ (c) $\dfrac{75}{\pi} \approx23.87^{\circ}$ (d) $225^{\circ}$
Recall: $$\text{Angle in degree } = \text{Angle in radian } \times \dfrac{180}{\pi}$$ (a) $$\theta= 1 \times \dfrac{180}{\pi} = \dfrac{180}{\pi} \approx 57.3^{\circ}$$ (b) $$\theta= \dfrac{\pi}{3} \times \dfrac{180}{\pi} = 60^{\circ}$$ (c) $$\theta=\dfrac{5}{12}\times \dfrac{180}{\pi}=\dfrac{75}{\pi} \approx23.87^{\circ}$$ (d) $$\theta = \dfrac{-3\pi}{4} \times \dfrac{180}{\pi} = -135^{\circ}$$ $\because \theta \text{ is equivalent to } \theta+360^{\circ}$ $$-135 = -135+360 =225^{\circ}$$