# Unit 10 Vocabulary

Polygon

A closed figure formed by three or more line segments

Concave Polygon

A polygon in which at least one interior angle has a measure more than 180°

Convex Polygon

A polygon in which each interior angle has a measure less than 180°

Regular Polygon

A polygon with equal angles and equal sides.

Vertex of a Polygon

The intersection of two sides of the polygon

The radius of a polygon's circumscribed circle

Apothem of a Polygon

A segment that is drawn from the center of a regular polygon perpendicular to a side of the polygon

Center of a Polygon

The center of a polygon

Central Angle of a Polygon

An angle formed by two consecutive radii. The angle is equal to 360°/n. 'n' is the symbol for number of sides

Interior Angle or a Polygon

An angle formed by two sides of a polygon with a common vertex

Exterior Angle or a Polygon

An angle formed by one side of a polygon and the extension of an adjacent side

Perimeter of a Polygon

The sum of the lengths of the sides of a polygon

Composite Area

Area of multiple polygons that are put together from many different parts

Area of a Polygon

A=½aP, where a is the apothem and P is the perimeter.