Meaning & use
concave polygon
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Meaning
nouncountable
A flat shape with straight sides in which at least one corner points inward, so some lines between corners pass outside the shape.
Grammar: Countable: a concave polygon, two concave polygons.
Patterns
- a concave polygon with n sides
The arrowhead shape is a concave polygon because one angle is larger than 180 degrees.
Students drew a concave polygon and then tried to draw a diagonal outside it.
A star is a concave polygon, unlike a square.
Word forms
| plural | concave polygons |
|---|
Common combinations
- a concave polygon with five sides
- The worksheet shows a concave polygon with five sides.
- identify a concave polygon
- Can you identify a concave polygon among these shapes?
- interior angle of a concave polygon
- One interior angle of a concave polygon exceeds 180 degrees.
- convex or concave polygon
- Decide whether each is a convex or concave polygon.
Synonyms and how they differ
- non-convex polygon
- Non-convex polygon means exactly the same thing but is the more formal phrase used in higher mathematics.
Opposites
Word family
Commonly confused: concave polygon or convex polygon?
concave polygon vs convex polygon
A convex polygon has no inward-pointing corner and all interior angles less than 180 degrees, the opposite of a concave polygon.
Practice
Which shape is a concave polygon?
Choose one answer.
A concave polygon has an inward dent, as an arrowhead does. A square, a regular hexagon and a triangle are all convex.
Make it your own
Write a sentence using “concave polygon”, then check it and compare it with the examples above.