Meaning & use
decagon
Last updated
UK/ˈdek.ə.ɡɒn/
US/ˈdek.ə.ɡɑːn/
Meaning
nouncountablemathematicstechnical
A flat shape with ten straight sides and ten corners.
Grammar: Countable: one decagon, two decagons.
Patterns
- a regular decagon
- the angles of a decagon
The students drew a decagon and counted its ten sides.
Each interior angle of a regular decagon measures 144 degrees.
The tile pattern included a decagon surrounded by smaller triangles.
Word forms
| plural | decagons |
|---|
Common combinations
- a regular decagon
- A regular decagon has ten equal sides and ten equal angles.
- draw a decagon
- Use a protractor to draw a decagon accurately.
- the area of a decagon
- We calculated the area of a decagon by splitting it into triangles.
- an irregular decagon
- An irregular decagon can have sides of different lengths.
Synonyms and how they differ
- ten-sided polygon
- This phrase explains the shape in plain words, while decagon is the compact technical name.
Word family
Commonly confused: decagon or decahedron?
decagon vs decahedron
A decahedron is a three-dimensional solid with ten faces, whereas a decagon is a flat shape with ten sides.
Practice
How many sides does a decagon have?
Choose one answer.
The prefix deca- means ten, so a decagon has ten sides. Eight is an octagon and nine is a nonagon.
Make it your own
Write a sentence using “decagon”, then check it and compare it with the examples above.
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