A 20-sided polygon is called an icosagon. Along with having 20 sides, all icosagons have 20 interior angles that add up to a total of 3240 degrees.
Know MoreRegular icosagons have sides of equal length and identical interior angles, each of which measures 162 degrees. Irregular icosagons on the other hand, have sides and angles of varying lengths. A famous example of an irregular icosagon is a swastika. Although this symbol has become stigmatized in the Western world because of its association with the Nazi Party, it has a long history of use in multiple cultures. For instance, in India swastikas are used to represent prosperity and well-being.
Learn more about ShapesA six-sided polygon is called a hexagon. A polygon is an enclosed figure with straight lines that do not cross over one another. Polygons do not necessarily have equal sides. A convex polygon has all angles pointing outward, but in a concave polygon, some angles can point inward.
Full Answer >A polygon with seven sides is called a heptagon. A polygon is a closed geometric shape that has at least three sides and angles.
Full Answer >A polygon with 10 sides is called a decagon. The word comes from the Greek words for "ten" ("deka") and for "angle" or "corner" ("gonia"). Decagons have 10 angles and 10 sides.
Full Answer >A nine-sided polygon is commonly called a nonagon. This polygon, which has nine edges, or vertices, is also called an enneagon. The term enneagon is preferable, but less popular than the name nonagon because the latter is simpler to spell and pronounce, according to Wolfram MathWorld.
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