If a regular polygon has a fixed edge length, can I know how many edges it has by knowing the length from...












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So I wonder if there is a formula so that when there's a defined edge length, I can calculate a regular polygon's edges amount by knowing its length from corner to center, or vice versa.



So let's say our defined edge length is 1, then by knowing the length from corner to center is square 2 to 2, I knows it's a square. And if the length is one, I know it's a hexagon.










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  • $begingroup$
    Note that if we join the center to two adjacent vertices of the polygon, we get an isosceles triangle with sides $l$, $r$ and $r$ where $l$ is side length and $r$ is the radius.
    $endgroup$
    – Faiq Irfan
    20 mins ago
















5












$begingroup$


So I wonder if there is a formula so that when there's a defined edge length, I can calculate a regular polygon's edges amount by knowing its length from corner to center, or vice versa.



So let's say our defined edge length is 1, then by knowing the length from corner to center is square 2 to 2, I knows it's a square. And if the length is one, I know it's a hexagon.










share|cite|improve this question







New contributor




Andrew-at-TW is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$












  • $begingroup$
    Note that if we join the center to two adjacent vertices of the polygon, we get an isosceles triangle with sides $l$, $r$ and $r$ where $l$ is side length and $r$ is the radius.
    $endgroup$
    – Faiq Irfan
    20 mins ago














5












5








5





$begingroup$


So I wonder if there is a formula so that when there's a defined edge length, I can calculate a regular polygon's edges amount by knowing its length from corner to center, or vice versa.



So let's say our defined edge length is 1, then by knowing the length from corner to center is square 2 to 2, I knows it's a square. And if the length is one, I know it's a hexagon.










share|cite|improve this question







New contributor




Andrew-at-TW is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




So I wonder if there is a formula so that when there's a defined edge length, I can calculate a regular polygon's edges amount by knowing its length from corner to center, or vice versa.



So let's say our defined edge length is 1, then by knowing the length from corner to center is square 2 to 2, I knows it's a square. And if the length is one, I know it's a hexagon.







polygons






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asked 26 mins ago









Andrew-at-TWAndrew-at-TW

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  • $begingroup$
    Note that if we join the center to two adjacent vertices of the polygon, we get an isosceles triangle with sides $l$, $r$ and $r$ where $l$ is side length and $r$ is the radius.
    $endgroup$
    – Faiq Irfan
    20 mins ago


















  • $begingroup$
    Note that if we join the center to two adjacent vertices of the polygon, we get an isosceles triangle with sides $l$, $r$ and $r$ where $l$ is side length and $r$ is the radius.
    $endgroup$
    – Faiq Irfan
    20 mins ago
















$begingroup$
Note that if we join the center to two adjacent vertices of the polygon, we get an isosceles triangle with sides $l$, $r$ and $r$ where $l$ is side length and $r$ is the radius.
$endgroup$
– Faiq Irfan
20 mins ago




$begingroup$
Note that if we join the center to two adjacent vertices of the polygon, we get an isosceles triangle with sides $l$, $r$ and $r$ where $l$ is side length and $r$ is the radius.
$endgroup$
– Faiq Irfan
20 mins ago










1 Answer
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$begingroup$

Yes. The quantity you are referring to is the radius of the polygon, and it has the formula
$$r=frac{s}{2sinleft(frac{180}{n}right)}$$
where $s$ is the side length of the polygon and $n$ is the number of sides. So given $r$ and $s$, you can simply solve the above equation for $n$.






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  • $begingroup$
    This is correct as far as it goes. It's worth pointing out that when you solve for $n$ there's no guarantee that it will turn out to be an integer, and hence correspond to a regular polygon.
    $endgroup$
    – Ethan Bolker
    19 mins ago











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









5












$begingroup$

Yes. The quantity you are referring to is the radius of the polygon, and it has the formula
$$r=frac{s}{2sinleft(frac{180}{n}right)}$$
where $s$ is the side length of the polygon and $n$ is the number of sides. So given $r$ and $s$, you can simply solve the above equation for $n$.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    This is correct as far as it goes. It's worth pointing out that when you solve for $n$ there's no guarantee that it will turn out to be an integer, and hence correspond to a regular polygon.
    $endgroup$
    – Ethan Bolker
    19 mins ago
















5












$begingroup$

Yes. The quantity you are referring to is the radius of the polygon, and it has the formula
$$r=frac{s}{2sinleft(frac{180}{n}right)}$$
where $s$ is the side length of the polygon and $n$ is the number of sides. So given $r$ and $s$, you can simply solve the above equation for $n$.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    This is correct as far as it goes. It's worth pointing out that when you solve for $n$ there's no guarantee that it will turn out to be an integer, and hence correspond to a regular polygon.
    $endgroup$
    – Ethan Bolker
    19 mins ago














5












5








5





$begingroup$

Yes. The quantity you are referring to is the radius of the polygon, and it has the formula
$$r=frac{s}{2sinleft(frac{180}{n}right)}$$
where $s$ is the side length of the polygon and $n$ is the number of sides. So given $r$ and $s$, you can simply solve the above equation for $n$.






share|cite|improve this answer









$endgroup$



Yes. The quantity you are referring to is the radius of the polygon, and it has the formula
$$r=frac{s}{2sinleft(frac{180}{n}right)}$$
where $s$ is the side length of the polygon and $n$ is the number of sides. So given $r$ and $s$, you can simply solve the above equation for $n$.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered 23 mins ago









kccukccu

9,261924




9,261924












  • $begingroup$
    This is correct as far as it goes. It's worth pointing out that when you solve for $n$ there's no guarantee that it will turn out to be an integer, and hence correspond to a regular polygon.
    $endgroup$
    – Ethan Bolker
    19 mins ago


















  • $begingroup$
    This is correct as far as it goes. It's worth pointing out that when you solve for $n$ there's no guarantee that it will turn out to be an integer, and hence correspond to a regular polygon.
    $endgroup$
    – Ethan Bolker
    19 mins ago
















$begingroup$
This is correct as far as it goes. It's worth pointing out that when you solve for $n$ there's no guarantee that it will turn out to be an integer, and hence correspond to a regular polygon.
$endgroup$
– Ethan Bolker
19 mins ago




$begingroup$
This is correct as far as it goes. It's worth pointing out that when you solve for $n$ there's no guarantee that it will turn out to be an integer, and hence correspond to a regular polygon.
$endgroup$
– Ethan Bolker
19 mins ago










Andrew-at-TW is a new contributor. Be nice, and check out our Code of Conduct.










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