The answer is 21.
I am not sure if you're looking for the answer, or the steps... get back to me foor help.
First you have to find the angle B (check attachment)

Then you can find the last angle inside the triangle, which I'll call C

Now you can find angle A

the answers is D cuz there is no line in the picture
10 total pieces of the pie
-5
-2
And only 3 remained so your answer would be
3/10