### Home > PC3 > Chapter 2 > Lesson 2.2.2 > Problem2-67

2-67.

​Roger is in an Algebra 2 class and has discovered the radian setting on his calculator. He has not learned about radians but would like to know what they are.

1. Explain to Roger how a radian is defined.

1 radian is the angle measure found by wrapping one radius around a circle.

2. What are the steps Roger needs to do to covert $240º$ to radians?

Us a Giante One of $\frac{\pi\text{ radians}}{180^{\circ}}$.

$240^\circ\cdot\frac{\pi\text{ radians}}{180^\circ}$

3. Show him how to change $\frac { 5 \pi } { 6 }$ radians to degrees.

$\frac{5\pi}{6}\cdot \frac{180^\circ}{\pi}=?$