How many types of pentagon are there?

There are several types of pentagons, primarily classified by their side lengths and angles. The most common types are regular pentagons, which have equal sides and angles, and irregular pentagons, which have sides and angles of varying lengths. Additionally, pentagons can be categorized based on their convexity; convex pentagons have all interior angles less than 180 degrees, while concave pentagons have at least one interior angle greater than 180 degrees.