As a kid, you might have come across different shapes in your geometry class. You may have learned about triangles, circles, and squares, but have you ever heard of a pentagon? If not, you’re in for a treat! In this article, we will explore the fascinating world of pentagons and learn how many sides a pentagon has.

### What is a Pentagon?

A pentagon is a geometric shape with five sides and five angles. It is a two-dimensional shape, which means it lies flat on a surface. The word ‘pentagon’ comes from two Greek words: ‘penta’ meaning ‘five’ and ‘gonia’ meaning ‘angle.’

### Types of Pentagons

Did you know that there are different types of pentagons? That’s right! Here are a few types of pentagons:

- Regular pentagon: A regular pentagon is a pentagon with all sides and angles equal.
- Irregular pentagon: An irregular pentagon is a pentagon with sides and angles that are not equal.
- Convex pentagon: A convex pentagon is a pentagon where all its interior angles are less than 180 degrees.
- Concave pentagon: A concave pentagon is a pentagon where one or more of its interior angles are greater than 180 degrees.

### How Many Sides Does a Pentagon Have?

As mentioned earlier, a pentagon has five sides. Each of its sides is equal in length to each other. Additionally, each interior angle of a regular pentagon measures 108 degrees. So, if you’re ever asked, “How many sides in a pentagon?” you’ll know the answer: Five!

### Fun Facts about Pentagons

Here are some cool facts about pentagons:

- The Pentagon, a building in Arlington, Virginia, is a pentagon-shaped building that serves as the headquarters of the United States Department of Defense.
- In nature, some starfish and sea urchins have a pentagonal shape.
- A soccer ball, also known as a football in some countries, is made up of 12 pentagons and 20 hexagons.

### Conclusion

In conclusion, a pentagon is a fascinating geometric shape that has five sides and five angles. It’s a two-dimensional shape that lies flat on a surface. You now know that there are different types of pentagons, including regular, irregular, convex, and concave. And, of course, you now know that a pentagon has five sides, each measuring the same length. So the next time someone asks, “How many sides in a pentagon?” you’ll know the answer!

## Want to Learn About Shapes for Free?

Khan Academy has hundreds of lessons for free. No ads, no subscriptions.