P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 5 · n = 27

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 = 27
ObjectiveMaximize circle radius

Record comparison

circle radius · Higher is better
RecordValue / intervalAuthor / holderSource
External best known[0.148137584794, 0.148137584796]Eckard SpechtPackomania ↗
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).
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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 = 27
LAYOUT & HISTORY

Starter layout

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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": "0.339120590",
      "y": "1.115080444"
    },
    {
      "turn": "0",
      "x": "0.339120590",
      "y": "0.818805274"
    },
    {
      "turn": "0",
      "x": "0.339282390",
      "y": "1.480039712"
    },
    {
      "turn": "0",
      "x": "0.364739198",
      "y": "0.512621983"
    },
    {
      "turn": "0",
      "x": "0.572650398",
      "y": "1.297406539"
    },
    {
      "turn": "0",
      "x": "0.613784525",
      "y": "1.004000745"
    },
    {
      "turn": "0",
      "x": "0.613784525",
      "y": "0.707725576"
    },
    {
      "turn": "0",
      "x": "0.653716526",
      "y": "1.582375413"
    },
    {
      "turn": "0",
      "x": "0.661043641",
      "y": "0.415243863"
    },
    {
      "turn": "0",
      "x": "0.861037515",
      "y": "1.370722433"
    },
    {
      "turn": "0",
      "x": "0.895558955",
      "y": "0.912446683"
    },
    {
      "turn": "0",
      "x": "0.895558955",
      "y": "0.616171513"
    },
    {
      "turn": "0",
      "x": "0.935490957",
      "y": "1.673929475"
    },
    {
      "turn": "0",
      "x": "0.942818071",
      "y": "0.323689801"
    },
    {
      "turn": "0",
      "x": "1.064790924",
      "y": "1.155632860"
    },
    {
      "turn": "0",
      "x": "1.142811945",
      "y": "1.462276496"
    },
    {
      "turn": "0",
      "x": "1.172485106",
      "y": "0.807133422"
    },
    {
      "turn": "0",
      "x": "1.172485106",
      "y": "0.510858252"
    },
    {
      "turn": "0",
      "x": "1.240980685",
      "y": "1.772086134"
    },
    {
      "turn": "0",
      "x": "1.252032372",
      "y": "0.224322954"
    },
    {
      "turn": "0",
      "x": "1.346565355",
      "y": "1.247186923"
    },
    {
      "turn": "0",
      "x": "1.425324484",
      "y": "0.961571840"
    },
    {
      "turn": "0",
      "x": "1.430961684",
      "y": "1.531187338"
    },
    {
      "turn": "0",
      "x": "1.468599525",
      "y": "0.520616706"
    },
    {
      "turn": "0",
      "x": "1.642745700",
      "y": "1.239691647"
    },
    {
      "turn": "0",
      "x": "1.642745700",
      "y": "0.760308353"
    },
    {
      "turn": "0",
      "x": "1.816891875",
      "y": "1.000000000"
    }
  ],
  "radius": "0.148137584"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 27,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.339120590",
      "y": "1.115080444"
    },
    {
      "turn": "0",
      "x": "0.339120590",
      "y": "0.818805274"
    },
    {
      "turn": "0",
      "x": "0.339282390",
      "y": "1.480039712"
    },
    {
      "turn": "0",
      "x": "0.364739198",
      "y": "0.512621983"
    },
    {
      "turn": "0",
      "x": "0.572650398",
      "y": "1.297406539"
    },
    {
      "turn": "0",
      "x": "0.613784525",
      "y": "1.004000745"
    },
    {
      "turn": "0",
      "x": "0.613784525",
      "y": "0.707725576"
    },
    {
      "turn": "0",
      "x": "0.653716526",
      "y": "1.582375413"
    },
    {
      "turn": "0",
      "x": "0.661043641",
      "y": "0.415243863"
    },
    {
      "turn": "0",
      "x": "0.861037515",
      "y": "1.370722433"
    },
    {
      "turn": "0",
      "x": "0.895558955",
      "y": "0.912446683"
    },
    {
      "turn": "0",
      "x": "0.895558955",
      "y": "0.616171513"
    },
    {
      "turn": "0",
      "x": "0.935490957",
      "y": "1.673929475"
    },
    {
      "turn": "0",
      "x": "0.942818071",
      "y": "0.323689801"
    },
    {
      "turn": "0",
      "x": "1.064790924",
      "y": "1.155632860"
    },
    {
      "turn": "0",
      "x": "1.142811945",
      "y": "1.462276496"
    },
    {
      "turn": "0",
      "x": "1.172485106",
      "y": "0.807133422"
    },
    {
      "turn": "0",
      "x": "1.172485106",
      "y": "0.510858252"
    },
    {
      "turn": "0",
      "x": "1.240980685",
      "y": "1.772086134"
    },
    {
      "turn": "0",
      "x": "1.252032372",
      "y": "0.224322954"
    },
    {
      "turn": "0",
      "x": "1.346565355",
      "y": "1.247186923"
    },
    {
      "turn": "0",
      "x": "1.425324484",
      "y": "0.961571840"
    },
    {
      "turn": "0",
      "x": "1.430961684",
      "y": "1.531187338"
    },
    {
      "turn": "0",
      "x": "1.468599525",
      "y": "0.520616706"
    },
    {
      "turn": "0",
      "x": "1.642745700",
      "y": "1.239691647"
    },
    {
      "turn": "0",
      "x": "1.642745700",
      "y": "0.760308353"
    },
    {
      "turn": "0",
      "x": "1.816891875",
      "y": "1.000000000"
    }
  ],
  "radius": "0.148137584"
}

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

DISCUSSION

Discussion

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