I had a problem with a question:

The daily consumption C (in gallons) of diesel fuel on a farm in modeled by

C= 30.3 +21.6sin[(2πt/365)+10.9]

where t is the time in days, with t=1 corresponding to January 1

A)What is the period of the model? Is it what you expected? Explain

B) What is the average daily fuel consumption? Which term of the model did you use? Explain?

C) Use a graphing utilty to graph the model. Use the graph to approximate the time of year when consumption exceeds 40 gallons per day

I have completely forgotten how to do sin functions and periods. I know this is probably a simple problem but I am having difficulty remembering how to do problems like this