How to model a diffuser in solidwork?
Check "Circular Sketch Pattern" under "Sketch tool". With this function, this problem should be easy.
Here's a very simple demo using the data you provided.
Answered with a tutorial: https://grabcad.com/tutorials/how-to-model-a-diffuser-in-solidwork
I hope the file I am attaching to this message gives you more ideas on the subject in case that you are already done with your project. There, you can easily access my drawings and see what I did. Didn't make it complicated.
Alright, hope everything goes well, goodbye.
(I couldn't upload the file, take a look at the message below for reference to the file in my grabcad profile's projects section.)