Which polygon has 10 sides?

A polygon with 10 sides is classified as a decagon. The term "decagon" is derived from the Greek words "deca," meaning ten, and "gon," meaning angle. Therefore, in geometrical terms, a decagon consists of ten straight sides and ten vertices.

To provide a clearer understanding, here’s a brief context for the other options: a heptagon is a seven-sided polygon, a nonagon has nine sides, and a dodecagon comprises twelve sides. This classification of polygons is beneficial in geometry as it helps in distinguishing various shapes based on their number of sides, and knowing the correct terminology is essential for effective communication and understanding in mathematics.