Using Phantom Command in Matlab

Hi, 

I have an assignment and I never used the Phantom command. I have to generate a 125x125 image.

My code so far is:

syms vars

A=phantom(125,125);

imshow(A) ---- This provided a standard image.

Going forward, I have to:

1. Generate and display the projection data between 0 degrees and 179 degrees using 25 degrees increments (7 projections), 10 degrees increments (17 projections) and 2 degrees increments (89 projections). (You may use the radon function in Matlab).

I have never used the radon function either, so I am very confused as to what I am supposed to do let alone how to start.

Please help!