degree radian conversion

[Guest]

I have an angle of 140 degrees. I converted it using my calculator to get 2.443 radians. I'm being asked to put into exact form. How do I do this? I know that exactfrom for 90 degrees is Pi/2. Thanks

 

[pka]

\(\displaystyle \L
360^ \circ \equiv 2\pi \quad \Rightarrow \quad \frac{{140^ \circ }}{{360^ \circ }} = \frac{r}{{2\pi }}\quad \Rightarrow \quad r = \frac{{7\pi }}{9}\).