Question #85 is true. It stands there and TELLS you how to convert from
degrees to radians. Right there, in Question #85, is everything you need to
know in order to do it. Please don't make something hard out of something
easy.
Take Question #86 as an example:
The angle is 80 degrees. According to the recipe in Question #85, you're
supposed to multiply 80 degrees by (pi)/180. Let's try it. It won't bite.
(80) x (pi/180) = (pi) x (80/180) .
Can you simplify the fraction (80/180) ? Divide the top and bottom by 20 ,
and you get 4/9 .
So the whole result is 4 pi / 9 . Son of a gun ! That's the 3rd choice on the list !