Angle

A dodecagon is a polygon with $12$ sides and $12$ angles. The interior angle of any polygon can be found out by the formula:

$\huge k=180(n-2)^{\circ}$ where $n$ is the number of sides or angles of the polygon and $k$ is the sum of the interior angles of the polygon.

Substituting $\large n=12$

We have,

$\begin{aligned}k&=180(n-2)^{\circ}\\&=180(12-2)^{\circ}\\&=180\times10^{\circ}\\&=1800^{\circ}\end{aligned}$

Dodecagon has $12$ sides.
Now, we know that a n-sided pokygon can be divided into (n - 2) non-overlapping triangles. If you dont know that then observe, a quadrilateral can be divided into 2 non-overlapping triangles, a pentagon into 3 non-overlapping triangles, a hexagon into 4 and so on.
So, a 12-sided figure can be divided into $12 - 2 = 10$ non-overlapping triangles.
Now, we know that the sum of the interior angles of a triangle is ${180}^°$ So, the sum total of all the interior angles of 10 triangles $= 10 × 180\\ = \boxed{{1800}^°}$

$\text{Note}$ :- All the non-overlapping triangles formed here are not degenerate.

A dodecagon has 12 sides.

Formula: $s=(n-2)(180)$

Substitute:

$s=(12-10)(180)=10(180)=\boxed{1800^\circ}$

It is simple. We can use the formula

$**(n-2)180=**$ sum of interior angles

Then Plug the values

$180(12-2)$

$=1800°$

NOTE: DODECAGON = 12 ANGLES AND 12 SIDES

(N-2)180=TOTAL INTERIOR ANGLE

N=12 (12-2)180=1800