Answer:
Step-by-step explanation:
Remark
If you take 1 vertex of your 12-gon and draw lines (excluding the lines from the vertex you have chosen) to the 10 other vertices you get 10 triangles. Each triangle has 180 degrees.
The total number of degrees in the interior of the 12-gon is 180 * 10 = 1800
Each interior angle is 1800/12 = 150
There is a formula that you can make
180 * (# sides - 2) / # sides
