INSTRUCTOR: In this video, I'm going to show you how to convert an angle in degrees to radian measure. I start out by taking my angle, 144 degrees, and I write it as a fraction over 1 so that I can multiply by the fraction pi over 180 degrees. That gives me 144 pi over 180. 

And now all I have to do is reduce 144 divided by 180. Both of these numbers divide by 36. So 144 divided by 36 is 4. 180 divided by 36 is 5. And so reduced, we have the radian measure 4 pi over 5.