The prefix "tri-" is related to the number three. That is why we call a three-sided polygon a triangle. Other words that begin with "tri" -
- tricycle: three-wheeled vehicle
- tripod: three-legged stand used to hold things steady like a camera or telescope
- triatholon: three event race, usually running, swimming, and bicycling.
The prefix "quad-" is related to the number four. So, we call a four-sided polygon a quadrilateral. Other words that begin with "quad" -
- quadruplet: one of four children born at the same time.
- quadraped: a four-legged animal
- quadrant: one of four parts created by two intersecting straight lines.
The prefix "penta-" is related with the number five. A five-sided polygon is called a pentagon. Other words that begin with "penta" -
- pentatholon: a sporting event composed of five separate events
- pentagram: a five-pointed star
The prefix "hexa-" is often related to the number six. A six-sided polygon is called a hexagon. Other words that begin with "hexa" -
- hexagram: a six-pointed star, also called the "Star of David"
- hexad: a group of six
- hexadecimal: base-16 number system (Don't worry if you haven't heard of this one - just take note of the six part of the 16.)
The prefix "hepta-" refers to the number seven. A seven-sided polygon is called a heptagon. Other words using this prefix are not very common.
The prefix "octa-" refers to the number eight. A eight-sided polygon is called a octagon. Other words using "octa-."
- octave: a distance of eight notes along a musical scale
- octopus: an animal in the ocean with eight legs covered with suction cups
- October: the tenth month (A long time ago, about 2000 years, October was the eighth month of the year.)
The prefix "poly-" refers to many. Polygon is used when we want to refer to many different figures with different numbers of sides. Other words using "poly-"
- polyantha: a type of rose bush that has many clusters of flowers
- polyester: man-made cloth, consists of many different chemical compounds
- polyglot: someone who can speak many languages.