How many sides does an octagon have?
An octagon has eight sides and eight angles. In a regular octagon, all sides are equal and each interior angle measures 135 degrees.
The word octagon comes from the Greek okto, meaning eight, the same root as octopus, which has eight arms, and October, which was the eighth month in the early Roman calendar. The interior angles of any octagon add up to 1,080 degrees.
The most famous octagon is the stop sign. In the United States and many other countries, stop signs are red octagons, a shape chosen in the 1920s so drivers could recognize them from a distance and even from behind. Its unique shape means people can identify it even if snow covers the word STOP.
Octagons around us
Octagons appear in architecture, such as the Dome of the Rock in Jerusalem and many old church baptisteries. Some umbrellas have eight panels, and mixed martial arts fights in the UFC take place in an eight-sided cage known as the Octagon. Many gazebos also have eight sides.
Did You Know?
Regular octagons cannot tile a floor on their own, but octagons combined with small squares create a popular tile pattern.