P82 · Packing and covering · Classic · Hard

Equal circles in regular polygons · m = 5 · n = 30

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 = 30
ObjectiveMaximize circle radius

Record comparison

circle radius · Higher is better
RecordValue / intervalAuthor / holderSource
External best known[0.141698173814, 0.141698173816]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).
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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 = 30
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": "0.332681179",
      "y": "1.212616721"
    },
    {
      "turn": "0",
      "x": "0.332681179",
      "y": "0.879464334"
    },
    {
      "turn": "0",
      "x": "0.332681179",
      "y": "0.546311947"
    },
    {
      "turn": "0",
      "x": "0.362304164",
      "y": "1.494460594"
    },
    {
      "turn": "0",
      "x": "0.561953641",
      "y": "1.046040528"
    },
    {
      "turn": "0",
      "x": "0.561953641",
      "y": "0.712888140"
    },
    {
      "turn": "0",
      "x": "0.591576626",
      "y": "1.327884400"
    },
    {
      "turn": "0",
      "x": "0.591576626",
      "y": "0.431044267"
    },
    {
      "turn": "0",
      "x": "0.679150913",
      "y": "1.597410343"
    },
    {
      "turn": "0",
      "x": "0.791226102",
      "y": "0.879464334"
    },
    {
      "turn": "0",
      "x": "0.820849087",
      "y": "1.161308207"
    },
    {
      "turn": "0",
      "x": "0.820849087",
      "y": "0.597620461"
    },
    {
      "turn": "0",
      "x": "0.908423374",
      "y": "1.430834150"
    },
    {
      "turn": "0",
      "x": "0.908423374",
      "y": "0.328094518"
    },
    {
      "turn": "0",
      "x": "0.995997662",
      "y": "1.700360093"
    },
    {
      "turn": "0",
      "x": "1.050121548",
      "y": "0.764196655"
    },
    {
      "turn": "0",
      "x": "1.098052544",
      "y": "1.220229620"
    },
    {
      "turn": "0",
      "x": "1.137695836",
      "y": "0.494670712"
    },
    {
      "turn": "0",
      "x": "1.185626832",
      "y": "1.489755564"
    },
    {
      "turn": "0",
      "x": "1.225270123",
      "y": "0.225144769"
    },
    {
      "turn": "0",
      "x": "1.239750718",
      "y": "0.974801184"
    },
    {
      "turn": "0",
      "x": "1.273201120",
      "y": "1.759281507"
    },
    {
      "turn": "0",
      "x": "1.327325006",
      "y": "0.705275241"
    },
    {
      "turn": "0",
      "x": "1.381448892",
      "y": "1.220229620"
    },
    {
      "turn": "0",
      "x": "1.414899293",
      "y": "0.435749298"
    },
    {
      "turn": "0",
      "x": "1.469023180",
      "y": "1.489755564"
    },
    {
      "turn": "0",
      "x": "1.523147066",
      "y": "0.974801184"
    },
    {
      "turn": "0",
      "x": "1.610721353",
      "y": "0.705275241"
    },
    {
      "turn": "0",
      "x": "1.664845240",
      "y": "1.220229620"
    },
    {
      "turn": "0",
      "x": "1.806543413",
      "y": "0.974801184"
    }
  ],
  "radius": "0.141698173"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 30,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.332681179",
      "y": "1.212616721"
    },
    {
      "turn": "0",
      "x": "0.332681179",
      "y": "0.879464334"
    },
    {
      "turn": "0",
      "x": "0.332681179",
      "y": "0.546311947"
    },
    {
      "turn": "0",
      "x": "0.362304164",
      "y": "1.494460594"
    },
    {
      "turn": "0",
      "x": "0.561953641",
      "y": "1.046040528"
    },
    {
      "turn": "0",
      "x": "0.561953641",
      "y": "0.712888140"
    },
    {
      "turn": "0",
      "x": "0.591576626",
      "y": "1.327884400"
    },
    {
      "turn": "0",
      "x": "0.591576626",
      "y": "0.431044267"
    },
    {
      "turn": "0",
      "x": "0.679150913",
      "y": "1.597410343"
    },
    {
      "turn": "0",
      "x": "0.791226102",
      "y": "0.879464334"
    },
    {
      "turn": "0",
      "x": "0.820849087",
      "y": "1.161308207"
    },
    {
      "turn": "0",
      "x": "0.820849087",
      "y": "0.597620461"
    },
    {
      "turn": "0",
      "x": "0.908423374",
      "y": "1.430834150"
    },
    {
      "turn": "0",
      "x": "0.908423374",
      "y": "0.328094518"
    },
    {
      "turn": "0",
      "x": "0.995997662",
      "y": "1.700360093"
    },
    {
      "turn": "0",
      "x": "1.050121548",
      "y": "0.764196655"
    },
    {
      "turn": "0",
      "x": "1.098052544",
      "y": "1.220229620"
    },
    {
      "turn": "0",
      "x": "1.137695836",
      "y": "0.494670712"
    },
    {
      "turn": "0",
      "x": "1.185626832",
      "y": "1.489755564"
    },
    {
      "turn": "0",
      "x": "1.225270123",
      "y": "0.225144769"
    },
    {
      "turn": "0",
      "x": "1.239750718",
      "y": "0.974801184"
    },
    {
      "turn": "0",
      "x": "1.273201120",
      "y": "1.759281507"
    },
    {
      "turn": "0",
      "x": "1.327325006",
      "y": "0.705275241"
    },
    {
      "turn": "0",
      "x": "1.381448892",
      "y": "1.220229620"
    },
    {
      "turn": "0",
      "x": "1.414899293",
      "y": "0.435749298"
    },
    {
      "turn": "0",
      "x": "1.469023180",
      "y": "1.489755564"
    },
    {
      "turn": "0",
      "x": "1.523147066",
      "y": "0.974801184"
    },
    {
      "turn": "0",
      "x": "1.610721353",
      "y": "0.705275241"
    },
    {
      "turn": "0",
      "x": "1.664845240",
      "y": "1.220229620"
    },
    {
      "turn": "0",
      "x": "1.806543413",
      "y": "0.974801184"
    }
  ],
  "radius": "0.141698173"
}

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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