A shape that has 11 sides is called a hendecagon, undecagon, or an endecagon. These are all names for a polygon that has 11 sides and 11 angles. The... See full answer below.

Learn how to name polygons, and see examples that walk through sample problems step-by-step for you to improve your math knowledge and skills.

Learn about polygons and see examples of polygons. Discover how to find angles in polygons and the difference between regular polygons and irregular polygons.

What is a ten-sided shape? A ten-sided shape is a decagon. The five-pointed star found on the United States flag is an example of a decagon.

Explore the nonagon and its size in this 5-minute video. Learn about the sides and angles of this 9-sided shape, then test your geometry knowledge with a quiz.

Dodecahedron What is a dodecahedron? A dodecahedron is a 12-sided 3D shape. Dodecahedrons come in many different shapes, since the faces can have any shape at all.

What is a quadrilateral shape? Learn about quadrilateral shapes, what shapes are parallelograms, and how a trapezoid shape is different from a parallelogram.

What is an irregular polygon? Learn the difference between a regular polygon and an irregular polygon, as well as irregular shapes. Learn how to find the area of irregular shapes through examples.

To put it another way, a polygon is a two-dimensional closed shape with at least three straight sides and three angles. One example of a polygon is a pentagon.

Explore the regular polygon and understand the equal sides of a polygon through examples. Study the parts of a polygon, as well as the types of regular polygons.