Octagon

What is an Octagon?

An octagon is a special shape with eight sides and eight corners. The word "octagon" comes from Ancient Greek. People love octagons because they appear in many places, like buildings and fun everyday things.

Where Can You Find Octagons?

You can spot octagons in some very interesting places! Famous buildings such as the Dome of the Rock in Jerusalem and the Tower of the Winds in Athens have octagonal designs. Even churches, like St. George's Cathedral, Addis Ababa and the Florence Baptistery, often feature this shape.

Fun Uses of Octagons

Octagons are not just for big buildings. Look closely and you’ll see them in many everyday items! For example, umbrellas sometimes have an octagonal outline. In many European countries and English-speaking places, stop signs are octagonal. Some games, like Janggi, use pieces that are octagonal. Even old video game controllers, such as the Nintendo 64 controller, have an octagonal shape around the analog stick.

Special Octagons

A regular octagon has all sides and angles the same. It is like a square with its corners cut off neatly. This shape has eight lines of reflective symmetry, meaning you can flip it in different ways and it will still look the same. Each internal angle in a regular octagon measures exactly 135°.

If you cut off more corners from an octagon, you can make a shape with even more sides, like a hexadecagon, which has sixteen sides! In three dimensions, shapes related to octagons can also exist, such as the rhombicuboctahedron.