Find the sum of the measure of the interior angles of each polygon. \( \begin{array}{l}\text { 4. Octagon } \\ 5.15 \text {-gon }\end{array} \)

To find the sum of the measure of the interior angles of a polygon, you can use the formula: \[ \text{Sum of interior angles} = (n - 2) \times 180^\circ \] where \(n\) is the number of sides. For the octagon (8 sides): \[ \text{Sum of interior angles} = (8 - 2) \times 180^\circ = 6 \times 180^\circ = 1080^\circ \] For the 15-gon (15 sides): \[ \text{Sum of interior angles} = (15 - 2) \times 180^\circ = 13 \times 180^\circ = 2340^\circ \] So, the sum of the measures of the interior angles of an octagon is \(1080^\circ\) and that of a 15-gon is \(2340^\circ\).