Ada explains that the properties of the shape mean that it is a polygon, a closed shape with straight sides. Zach’s shape is a decagon, because it has 10 ... examples of regular and irregular ...

Polygons can be regular or irregular in shape ... × 180. This gives (10 – 2) × 180 = 1440 Image caption, Find the sum of the interior angles of a 26-sided polygon. It would not be practical ...