1. ## Geometry

Can I make a word like 'three-angle shape' for a triangle, 'four-angle' for rectangle, etc.
So I could call any shape I don't know its name, like 'five-angle', 'eight-angle', etc.
Or you may use another formula?

2. ## Re: Geometry

[AmE - not a teacher]

We can, but we usually used "sided". Four-sided, five-sided, etc.

Also, I would say three-angled, four-angled, etc. (but this is very uncommon)

3. ## Re: Geometry

You could say a shape contains three angles.

4. ## Re: Geometry

Originally Posted by atabitaraf
Can I make a word like 'three-angle shape' for a triangle, 'four-angle' for rectangle, etc.
So I could call any shape I don't know its name, like 'five-angle', 'eight-angle', etc.
Or you may use another formula?
There are words already, like pentagon, hexagon, heptagon, octagon, etc.

5. ## Re: Geometry

Note that a rectangle is not just a figure with four angles. "Rectus" means right in Latin. And a rectangle is a plane figure whose all angles are right. The names for a figure with four angles are: "quadrilateral", "tetragon" or "quadrangle".

6. ## Re: Geometry

Originally Posted by SoothingDave
There are words already, like pentagon, hexagon, heptagon, octagon, etc.

Respectfully, a pentagon is a five-sided polygon, not typically a five-angled one, which I think was the original question.

7. ## Re: Geometry

But given the two descriptions 'This polygon has five sides' and 'This polygon contains five angles', one's conclusions about the figure will be the same: it is a pentagon.

b

8. ## Re: Geometry

Originally Posted by BobSmith
Respectfully, a pentagon is a five-sided polygon, not typically a five-angled one, which I think was the original question.
And as angles are formed at vertices, how many shapes (excluding, of course, the circle) with different numbers of sides and numbers of angles do you know? I think Dave was trying to explain that there is a already a pattern to the names of these shapes which the OP could use, rather than trying to generate his own names via a pattern that does not sound natural to a native ear.

9. ## Re: Geometry

Originally Posted by Tullia
rather than trying to generate his own names via a pattern that does not sound natural to a native ear.
Right, which is why I provided the pattern that is natural to the ear: X-sided. That's what we use. We don't use words we don't know. How else would you ask "What is a 117-sided polygon called?"

10. ## Re: Geometry

Originally Posted by BobK
But given the two descriptions 'This polygon has five sides' and 'This polygon contains five angles', one's conclusions about the figure will be the same: it is a pentagon.

b
Indeed, although one might be inclined to doubt that on seeing this pentagon.

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