Ohio Assessments for Educators (OAE) Mathematics Practice Exam

A decagon is defined as a polygon that has ten sides. The prefix "deca-" is derived from the Greek word for ten, making it quite straightforward to associate this term with its corresponding number of sides. A decagon can also be classified as either a regular or irregular polygon. In a regular decagon, all sides and angles are equal. When counting the sides of a polygon, it is essential to rely on the terminology specific to the shape, and understanding these prefixes can help clarify the properties of various polygons. Thus, identifying a decagon as having ten sides aligns perfectly with its definition in geometry.