Answer:
1120°
Explanation:
Use the sum of interior angles formula:
![180(n-2)](https://img.qammunity.org/2023/formulas/mathematics/college/kaxgcai1s1bljrdoe9whl7fqrdyzumfhp7.png)
Where n is the number of sides.
In a nonagon, there are 9 sides, substitute 9 for n:
![180(9-2)\\180(7)\\1260](https://img.qammunity.org/2023/formulas/mathematics/high-school/g0u6g2jgr3d2bxkqk1nkb27gqvffy62ne6.png)
Since our nonagon is a regular nonagon, all 9 angles measure the same, so each angle measures:
![(1260)/(9) =140](https://img.qammunity.org/2023/formulas/mathematics/high-school/ixc42dgx3p3x5duwpz51g90zwbwsfycpa9.png)
Subtract 140 from 1260:
![1260-140=1120](https://img.qammunity.org/2023/formulas/mathematics/high-school/dftnnm7i395i3a1phynipbvu2u1rjx0mth.png)