P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 5 · n = 35

Pack n equal circles into the regular m-gon with centre (1,1), circumradius 1, and first vertex (2,1) so as to maximise their common radius.

Instancem = 5 · n = 35
ObjectiveMaximize circle radius

Record comparison

circle radius · Higher is better
RecordValue / intervalAuthor / holderSource
External best known[0.130170592941, 0.130170592943]Paolo AmorePackomania ↗
Site recordNo player record yet——

Formal definition

  • ContainerThe editor and certificate normalise the container to the exact regular m-gon with centre (1,1), circumradius 1, and first vertex (2,1), while public scores follow the literature convention. Boundary contact is allowed.
  • SubmissionSubmit {radius, placements:[{x,y,turn},…]}, with each value written as a decimal string of at most nine places. Here x, y are centre coordinates; circles require turn = 0 and polygons use turn = tan(θ/2). Coordinates and turn must lie in [−4, 4], with 0 < radius ≤ 4.
  • ConstraintsExactly n congruent pieces lie wholly inside the container with pairwise disjoint interiors. Polygons may rotate independently by arbitrary angles.
  • PrecisionInput decimals are parsed as exact rationals and regular-polygon vertices are defined algebraically, with zero floating-point tolerance in feasibility checks.
  • ObjectiveMaximise the circle radius r (with container circumradius fixed at 1).
Open full editor ↗

Layout shown: starter layout

VERIFIED CONSTRUCTIONVERIFIED CONSTRUCTION

Getting a feel for it

Literature targets and coordinate certificates

Literature targets are converted at their published precision, while nine-decimal coordinate certificates are stored and displayed alongside the source values. Pentagon and hexagon rows n = 41–100 and octagon rows n = 41–48 cite Packomania's value and author without importing its coordinates; they start from an ordinary site grid baseline.

Source
The current arrangement for Equal circles in regular polygons m = 5 · n = 35
LAYOUT & HISTORY

Starter layout

Inspect the layout, solver notes and record history.

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ANSWER FORMAT

How to write your answer

the regular m-gon with centre (1,1), circumradius 1, and first vertex (2,1)

Submit {radius, placements:[{x,y,turn},…]}, with each value written as a decimal string of at most nine places. Here x, y are centre coordinates; circles require turn = 0 and polygons use turn = tan(θ/2). Coordinates and turn must lie in [−4, 4], with 0 < radius ≤ 4.

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.321153599",
      "y": "1.420770104"
    },
    {
      "turn": "0",
      "x": "0.321153599",
      "y": "1.076955627"
    },
    {
      "turn": "0",
      "x": "0.321153599",
      "y": "0.816614441"
    },
    {
      "turn": "0",
      "x": "0.321153599",
      "y": "0.556273255"
    },
    {
      "turn": "0",
      "x": "0.516666858",
      "y": "1.248862865"
    },
    {
      "turn": "0",
      "x": "0.538635809",
      "y": "1.563875034"
    },
    {
      "turn": "0",
      "x": "0.550130647",
      "y": "0.953072438"
    },
    {
      "turn": "0",
      "x": "0.550130647",
      "y": "0.692731252"
    },
    {
      "turn": "0",
      "x": "0.550130647",
      "y": "0.432390066"
    },
    {
      "turn": "0",
      "x": "0.736173866",
      "y": "1.388842172"
    },
    {
      "turn": "0",
      "x": "0.748579453",
      "y": "1.128282220"
    },
    {
      "turn": "0",
      "x": "0.786234990",
      "y": "1.644324885"
    },
    {
      "turn": "0",
      "x": "0.797729828",
      "y": "0.872622587"
    },
    {
      "turn": "0",
      "x": "0.797729828",
      "y": "0.612281402"
    },
    {
      "turn": "0",
      "x": "0.797729828",
      "y": "0.351940216"
    },
    {
      "turn": "0",
      "x": "0.983773048",
      "y": "1.469292022"
    },
    {
      "turn": "0",
      "x": "0.998939153",
      "y": "1.037826523"
    },
    {
      "turn": "0",
      "x": "1.023191909",
      "y": "0.482110809"
    },
    {
      "turn": "0",
      "x": "1.033834172",
      "y": "1.724774736"
    },
    {
      "turn": "0",
      "x": "1.050021707",
      "y": "0.762794150"
    },
    {
      "turn": "0",
      "x": "1.129082209",
      "y": "0.244277301"
    },
    {
      "turn": "0",
      "x": "1.136797757",
      "y": "1.258671579"
    },
    {
      "turn": "0",
      "x": "1.242688057",
      "y": "1.496505086"
    },
    {
      "turn": "0",
      "x": "1.257387391",
      "y": "1.006488981"
    },
    {
      "turn": "0",
      "x": "1.261045820",
      "y": "0.587955269"
    },
    {
      "turn": "0",
      "x": "1.292749181",
      "y": "1.751987800"
    },
    {
      "turn": "0",
      "x": "1.366936120",
      "y": "0.350121762"
    },
    {
      "turn": "0",
      "x": "1.395245995",
      "y": "1.227334036"
    },
    {
      "turn": "0",
      "x": "1.414070530",
      "y": "0.798575713"
    },
    {
      "turn": "0",
      "x": "1.501136295",
      "y": "1.465167544"
    },
    {
      "turn": "0",
      "x": "1.519960830",
      "y": "0.560742205"
    },
    {
      "turn": "0",
      "x": "1.567095239",
      "y": "1.009196157"
    },
    {
      "turn": "0",
      "x": "1.654161005",
      "y": "1.254547101"
    },
    {
      "turn": "0",
      "x": "1.672985539",
      "y": "0.771362649"
    },
    {
      "turn": "0",
      "x": "1.837407658",
      "y": "0.999999993"
    }
  ],
  "radius": "0.130170592"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 35,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.321153599",
      "y": "1.420770104"
    },
    {
      "turn": "0",
      "x": "0.321153599",
      "y": "1.076955627"
    },
    {
      "turn": "0",
      "x": "0.321153599",
      "y": "0.816614441"
    },
    {
      "turn": "0",
      "x": "0.321153599",
      "y": "0.556273255"
    },
    {
      "turn": "0",
      "x": "0.516666858",
      "y": "1.248862865"
    },
    {
      "turn": "0",
      "x": "0.538635809",
      "y": "1.563875034"
    },
    {
      "turn": "0",
      "x": "0.550130647",
      "y": "0.953072438"
    },
    {
      "turn": "0",
      "x": "0.550130647",
      "y": "0.692731252"
    },
    {
      "turn": "0",
      "x": "0.550130647",
      "y": "0.432390066"
    },
    {
      "turn": "0",
      "x": "0.736173866",
      "y": "1.388842172"
    },
    {
      "turn": "0",
      "x": "0.748579453",
      "y": "1.128282220"
    },
    {
      "turn": "0",
      "x": "0.786234990",
      "y": "1.644324885"
    },
    {
      "turn": "0",
      "x": "0.797729828",
      "y": "0.872622587"
    },
    {
      "turn": "0",
      "x": "0.797729828",
      "y": "0.612281402"
    },
    {
      "turn": "0",
      "x": "0.797729828",
      "y": "0.351940216"
    },
    {
      "turn": "0",
      "x": "0.983773048",
      "y": "1.469292022"
    },
    {
      "turn": "0",
      "x": "0.998939153",
      "y": "1.037826523"
    },
    {
      "turn": "0",
      "x": "1.023191909",
      "y": "0.482110809"
    },
    {
      "turn": "0",
      "x": "1.033834172",
      "y": "1.724774736"
    },
    {
      "turn": "0",
      "x": "1.050021707",
      "y": "0.762794150"
    },
    {
      "turn": "0",
      "x": "1.129082209",
      "y": "0.244277301"
    },
    {
      "turn": "0",
      "x": "1.136797757",
      "y": "1.258671579"
    },
    {
      "turn": "0",
      "x": "1.242688057",
      "y": "1.496505086"
    },
    {
      "turn": "0",
      "x": "1.257387391",
      "y": "1.006488981"
    },
    {
      "turn": "0",
      "x": "1.261045820",
      "y": "0.587955269"
    },
    {
      "turn": "0",
      "x": "1.292749181",
      "y": "1.751987800"
    },
    {
      "turn": "0",
      "x": "1.366936120",
      "y": "0.350121762"
    },
    {
      "turn": "0",
      "x": "1.395245995",
      "y": "1.227334036"
    },
    {
      "turn": "0",
      "x": "1.414070530",
      "y": "0.798575713"
    },
    {
      "turn": "0",
      "x": "1.501136295",
      "y": "1.465167544"
    },
    {
      "turn": "0",
      "x": "1.519960830",
      "y": "0.560742205"
    },
    {
      "turn": "0",
      "x": "1.567095239",
      "y": "1.009196157"
    },
    {
      "turn": "0",
      "x": "1.654161005",
      "y": "1.254547101"
    },
    {
      "turn": "0",
      "x": "1.672985539",
      "y": "0.771362649"
    },
    {
      "turn": "0",
      "x": "1.837407658",
      "y": "0.999999993"
    }
  ],
  "radius": "0.130170592"
}

Submit {radius, placements:[{x,y,turn},…]}, with each value written as a decimal string of at most nine places. Here x, y are centre coordinates; circles require turn = 0 and polygons use turn = tan(θ/2). Coordinates and turn must lie in [−4, 4], with 0 < radius ≤ 4. · Verifier v1.0.0

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