Posted by Calculus on .
A runner sprints around a circular track of radius 150 m at a constant speed of 7 m/s. The runner's friend is standing at a distance 300 m from the center of the track. How fast is the distance between the friends changing when the distance between them is 300 m? (Round to 2 decimal places.)
I get how to do related rates. But I have no idea where to start with this question. I know we have to use the formula c^2= a^2 + b^2  2(ab)cosC but that's it

Related Rates Problem 
Josh,
your kind of really bad at this