To form a triangle, we need to choose 3 vertices from the dodecagon.
There are 12 vertices to choose from, so we can choose 3 vertices in ${12 \choose 3} = \frac{12!}{3!9!} = \frac{12 \cdot 11 \cdot 10}{3 \cdot 2 \cdot 1} = \boxed{220}$ ways.
The answer is: 220
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
How many triangles can be formed using the vertices of a regular dodecagon (a 12-sided polygon)?

### Answer:
