The sum of the measures of the interior angles of a polygon is given by the formula:
[tex]\text{ Sum of interior angles=(n-2)x180}\degree[/tex]Where n is the number of sides of the polygon, in this case the 25-gon has 25 sides, then the sum of its interior angles is:
[tex]\begin{gathered} \text{ Sum of interior angles=(25-2)x180}\degree \\ \text{ Sum of interior angles=(23)x180}\degree \\ \text{ Sum of interior angles=}4140\degree \end{gathered}[/tex]