The sum of the measures of the exterior angles of any polygon, regardless of the number of sides, is always 360 degrees. This rule holds true for a decagon, which has ten sides, just as it does for triangles, quadrilaterals, and any other polygon.
To explain further, exterior angles are formed when a side of a polygon is extended. The exterior angle is supplementary to the interior angle, meaning they add up to 180 degrees. If you were to measure each of the ten exterior angles of a decagon and add them together, you’d find that they equal 360 degrees. It’s a simple and interesting property of polygons that makes calculations involving exterior angles straightforward.