For this case we have that by definition, the sum of the internal angles of a polygon of n sides is given by:
![(n-2) * 180](https://img.qammunity.org/2020/formulas/mathematics/middle-school/d8j3m8v0g2vcfo0m7rfdkdbcmfxn3fcjhr.png)
Where:
n: Represents the number of sides
According to the data, we have a 12-sided polygon, so
![n = 12:](https://img.qammunity.org/2020/formulas/mathematics/middle-school/495hc0h97logh14yqy4p7uy5kwxznk5af7.png)
![(12-2) * 180 = 10 * 180 = 1800](https://img.qammunity.org/2020/formulas/mathematics/middle-school/hq2ofdx5567hlvsy67qvn0emonomm9py0c.png)
Thus, the sum of the internal angles is 1800 degrees.
Answer:
1800 degrees