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.