In cases like these, you simply have to multiply the choices you have for each step.
In fact, you can choose between 4 different crusts. For each of these crusts you can choose 4 different sauces. This means that there are
choices at this point. In fact, if we call the crust options 1,2,3,4 and the sauce options A,B,C,D, the 16 possible combinations are

From here, you keep going multiplying the number of options for each step, for a total of

Answer:
What's the question?
Step-by-step explanation:
Answer:
∠2 = 51°
Step-by-step explanation:
The sum of supplementary angles = 180°
Equate the sum of the angles to 180 and solve for a
11a + 19 + 6a - 9 = 180
17a + 10 = 180 ( subtract 10 from both sides )
17a = 170 ( divide both sides by 17 )
a = 10
Hence
∠2 = (6 × 10) - 9 = 60 - 9 = 51°