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1 vote
1 answer
332 views

Polygon Diagonal Combinatorics

A diagonal for a polygon is defined as the line segment joining two non-adjacent points. Given an n-sided polygon, how many different diagonals can be drawn for this polygon? I know that the number of ...
dumon__'s user avatar
  • 150
2 votes
1 answer
393 views

Number of isoceles triangles formed by the vertices of a polygon that are not equilateral

QUESTION: Let $A_1,A_2,...,A_n$ be the vertices of a regular polygon with $n$ sides. How many of the triangles $△A_iA_jA_k,1 ≤ i < j < k ≤ n,$ are isosceles but not equilateral? MY APPROACH: ...
Stranger Forever's user avatar
0 votes
1 answer
178 views

Number of ways to choose a closed path of given length on a square lattice

Also known as self-avoiding polygons, this is an unsolved problem. However, to leading order in the asymptotic limit, the number of polygons of a given perimeter scales exponentially with perimeter ...
Kai's user avatar
  • 1,191
4 votes
2 answers
5k views

Ways to create a quadrilateral by joining vertices of regular polygon with no common side to polygon

How many ways are there to create a quadrilateral by joining vertices of a $n$- sided regular polygon with no common side to that polygon? It's quite easy to solve for triangles for the same question,...
Mrigank's user avatar
  • 199
23 votes
4 answers
93k views

How many triangles can be formed by the vertices of a regular polygon of $n$ sides?

How many triangles can be formed by the vertices of a regular polygon of $n$ sides? And how many if no side of the polygon is to be a side of any triangle ? I have no idea where I should start to ...
Bsonjin's user avatar
  • 335
22 votes
8 answers
3k views

Number of ways to connect sets of $k$ dots in a perfect $n$-gon

Let $Q(n,k)$ be the number of ways in which we can connect sets of $k$ vertices in a given perfect $n$-gon such that no two lines intersect at the interior of the $n$-gon and no vertex remains ...
Matan's user avatar
  • 821
0 votes
0 answers
331 views

Solving the "Library of Babel" puzzle, but for polygons.

The Library of Babel is a story about a universe whose contents are every possible 410-page book that could possibly exist. After a conversation with someone about doing this with images, and coming ...
Polynomial's user avatar