What do you call a shape with 7 or 9 points?

Triangle= trigon
Square= quadragon
5 points= hectagon
6 points= hexagon
7 points=?
8 points= octagon
9 points= ?
10 points= decagon

These are all concidered polygons right?

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ArishMell · 70-79, M

It's always a triangle for 3 sides / apices; but the root "trigon" is of course half of the word trigonometry; the mathematics of ttiangles and angles.

5 points = pentagon. ("hect[o]" is the prefix for 100 in SI units, e.g. 1 hectometre = 100 metres).

7 points = septagon

9 points = nonagon.

11 points = ? I'm not sure it has a name!

12 points = dodecagon.

(A 12-facet solid is a dodecahedronm, and each facet of a regular dodecahedron is a regular pentagon in outline. I once made a pomander to that shape, approximately three inches across, as a Christmas present to a girlfriend. This is a common shape for military radar and radio aerial enclosures.)

GuyWithOpinions · 31-35, M

@ArishMell nice! Good info. Thanks 👍

SpudMuffin · 61-69, M

5 = pentagon
7 = heptagon
9 = nonagon

I've never seen trigon or quadragon used, though I suppose technically they are correct.

GuyWithOpinions · 31-35, M

@SpudMuffin thanks i was curious

SpudMuffin · 61-69, M

@GuyWithOpinions you're welcome.

SomeMichGuy · M

@SpudMuffin Hept- & Non- yes.

MaBalzEsHari · M

I'd call it a 7 or 9 point thingy.

SomeMichGuy · M

Triangle is a 3-point, 3-sided plane figure.

Square is special, not a general name for any 4-point/4-sided plane figure (quadrilateral).

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SomeMichGuy · M

@GuyWithOpinions A square is a subset of 4-pointed/4-sided plane figures, yes, but it is not the generic term for such a figure (it's actually a degenerate quadrilateral).

A triangle IS a generic terms for a 3-pointed/3-sided plane figure with straight sides.

GuyWithOpinions · 31-35, M

@SomeMichGuy a triangle is a shape. A trigon is any polygon with 3 points. But the only shape you can make with 3 points is a triangle 🤯

SomeMichGuy · M

@GuyWithOpinions A polygon is a superset of shapes.

A triangle is the only polygon of 3 sides/vertices.

Yes

PalteseMalconFunch · 36-40, T

As long as they have straight edges and are continuous it’s a polygon however many sides it has.

Give it infinite sides are you get a circle

scorpiolovedeep · 51-55, M

Heptagon

And

Nonagon

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