I need to find the equation of the sine graph below

I was able to find a, k, and c but how do I find d?

So far I have f(x) = 5 sin (x - d) + 2

I know I'm at the right track since the answer was given, y = 5 sin (x + π/3) + 2. What I want to know is how they got π/3, I think I can just plug in a point but I don't know how to solve it without ending up with a decimal answer.