91Ó°ÊÓ

The theorem for the sum of interior angles for convex polygon states that the sum of measures of the interior angles of a convex polygon with sides is $\left(n-2\right)180$.

The number of sides in a Decagon is 10.

Therefore, the value of$n$ is 10.

By using the theorem for the sum of interior angles for convex polygon, the sum of the interior angles for the polygon having 10 sides is given by:

$$\begin{gathered} \left(10−2\right)180=8×180 \\ =1440 \end{gathered}$$

Therefore, the sum of interior angles for the Decagon is $1440°$.

The theorem for the sum of exterior angles for convex polygon states that the sum of measures of the exterior angles of a convex polygon is $360°$.

The number of sides in a Decagon is 10.

Therefore, the value of$n$ is 10.

By using the theorem for the sum of exterior angles for convex polygon, the sum of the exterior angles for the polygon having 10 sides is $360°$.

Therefore, the sum of exterior angles of the Decagon is $360°$.