Chapter 3 - Radian Measure and the Unit Circle - Section 3.3 The Unit Circle and Circular Functions - 3.3 Exercises - Page 125: 84

Since $x$ is positive and $y$ is negative, an angle of 49 radians is in the fourth quadrant.

$\frac{x}{r} = cos~\theta$ $\frac{x}{r} = cos~(49~rad)$ $\frac{x}{r} = 0.30$ Since $r$ is always positive, $x$ is positive. $\frac{y}{r} = sin~\theta$ $\frac{y}{r} = sin~(49~rad)$ $\frac{y}{r} = -0.95$ Since $r$ is always positive, $y$ is negative. Since $x$ is positive and $y$ is negative, an angle of 49 radians is in the fourth quadrant.