The radian measure equivalent to 150º is

What Stu has said is correct.

$$\begin{array}{rll}
360^0&=&2\pi\\\\
180^0&=&\pi\\\\
1^0&=&\frac{\pi}{180}\\\\
150^0&=&\frac{150\pi}{180}\\\\
150^0&=&\frac{5\pi}{6}\\\\
150^0&\approx&2.618\;\;radians\\\\

\end{array}$$

 5π
 6  = 5· π
6 = 5· 30° = 150°

There is plenty of google answers for this. 

1. Therefore, there are  2 pi radians in a full circle. We also know that there are 360 degrees in a circle. So, there are 360 degrees per  2 pi radians. Dividing 360 by 2 pi give us the value of about  57.2957 degrees per radian.
   
   Additionally, you can use a calculator online to calculate this. If you want to know how to calculate it there should be a different question. 
   
   A calculated answer to op's question gives 2.617993878 radian for 150 degrees. Which is 150 / value for radian. 
   
   I do not know what anonymous post was describing. This is information you can check online. Hope that helps.