P84 · Packing and covering · Classic · Hard

Equilateral triangles in a disc · n = 34

Pack n unit-side equilateral triangles into a disc. Contact is allowed; interiors cannot overlap. Minimise the container circle radius.

Instancen = 34
ObjectiveMinimize container circle radius

Record comparison

container circle radius · Lower is better
RecordValue / intervalAuthor / holderSource
External best known[2.37504, 2.37505)Thomas SchadtErich Friedman ↗
Site recordNo player record yet——

Formal definition

  • ContainerThe editor and certificate normalise the container to the closed unit disc centred at (1,1), while public scores are reported in the literature's unit-piece scale. 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.
  • ObjectiveContainer circle radius = 1/(2 sin(π/3) r), where smaller is better. Pages, leaderboards, and literature records share this unit with automatic conversion.
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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.

Source
The current arrangement for Equilateral triangles in a disc n = 34
LAYOUT & HISTORY

Starter layout

Inspect the layout, solver notes and record history.

Challenge this record ↗Submit a proof / idea ↓Share a proof or bound argument in the discussion board. Accepted contributions earn proof points.
ANSWER FORMAT

How to write your answer

the closed unit disc centred at (1,1)

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": "0.200541705",
      "x": "1.166948108",
      "y": "1.826557881"
    },
    {
      "turn": "0.200541705",
      "x": "0.795376300",
      "y": "1.770031036"
    },
    {
      "turn": "-0.337707806",
      "x": "0.571082582",
      "y": "1.676301008"
    },
    {
      "turn": "0.200541705",
      "x": "1.471459241",
      "y": "1.624551129"
    },
    {
      "turn": "-0.337707806",
      "x": "0.988695744",
      "y": "1.622651992"
    },
    {
      "turn": "-0.337707806",
      "x": "1.664778685",
      "y": "1.477172085"
    },
    {
      "turn": "0.200541705",
      "x": "0.540108308",
      "y": "1.435191937"
    },
    {
      "turn": "-0.337707806",
      "x": "0.280824915",
      "y": "1.425191366"
    },
    {
      "turn": "-0.337707806",
      "x": "1.279756130",
      "y": "1.403001680"
    },
    {
      "turn": "0.200541705",
      "x": "0.957721470",
      "y": "1.381542921"
    },
    {
      "turn": "-0.337707806",
      "x": "0.733427752",
      "y": "1.287812893"
    },
    {
      "turn": "0.200541705",
      "x": "1.611799267",
      "y": "1.238889923"
    },
    {
      "turn": "0.200541705",
      "x": "0.249850641",
      "y": "1.184082294"
    },
    {
      "turn": "0.200541705",
      "x": "1.248781856",
      "y": "1.161892609"
    },
    {
      "turn": "-0.337707806",
      "x": "1.805118710",
      "y": "1.091510879"
    },
    {
      "turn": "-0.337707806",
      "x": "1.024488138",
      "y": "1.068162581"
    },
    {
      "turn": "0.200541705",
      "x": "0.702453478",
      "y": "1.046703822"
    },
    {
      "turn": "-0.337707806",
      "x": "0.443170085",
      "y": "1.036703250"
    },
    {
      "turn": "-0.337707806",
      "x": "1.442101300",
      "y": "1.014513565"
    },
    {
      "turn": "0.200541705",
      "x": "1.774144436",
      "y": "0.850401807"
    },
    {
      "turn": "0.097516661",
      "x": "0.160083974",
      "y": "0.834615666"
    },
    {
      "turn": "0.200541705",
      "x": "0.993513864",
      "y": "0.827053510"
    },
    {
      "turn": "0.200541705",
      "x": "1.411127026",
      "y": "0.773404494"
    },
    {
      "turn": "0.081086445",
      "x": "0.581745452",
      "y": "0.709595637"
    },
    {
      "turn": "-0.337707806",
      "x": "1.186833308",
      "y": "0.679674466"
    },
    {
      "turn": "-0.454258290",
      "x": "0.335778629",
      "y": "0.665315059"
    },
    {
      "turn": "-0.337707806",
      "x": "1.604446470",
      "y": "0.626025450"
    },
    {
      "turn": "-0.337707806",
      "x": "0.824698912",
      "y": "0.552267139"
    },
    {
      "turn": "0.200541705",
      "x": "1.134531252",
      "y": "0.441305286"
    },
    {
      "turn": "0.200541705",
      "x": "1.552144414",
      "y": "0.387656270"
    },
    {
      "turn": "0.473394652",
      "x": "0.457396572",
      "y": "0.337887904"
    },
    {
      "turn": "0.200541705",
      "x": "0.793724638",
      "y": "0.311158068"
    },
    {
      "turn": "-0.337707806",
      "x": "1.327850696",
      "y": "0.293926242"
    },
    {
      "turn": "-0.337707806",
      "x": "0.987044082",
      "y": "0.163779024"
    }
  ],
  "radius": "0.243090496"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 34,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0.200541705",
      "x": "1.166948108",
      "y": "1.826557881"
    },
    {
      "turn": "0.200541705",
      "x": "0.795376300",
      "y": "1.770031036"
    },
    {
      "turn": "-0.337707806",
      "x": "0.571082582",
      "y": "1.676301008"
    },
    {
      "turn": "0.200541705",
      "x": "1.471459241",
      "y": "1.624551129"
    },
    {
      "turn": "-0.337707806",
      "x": "0.988695744",
      "y": "1.622651992"
    },
    {
      "turn": "-0.337707806",
      "x": "1.664778685",
      "y": "1.477172085"
    },
    {
      "turn": "0.200541705",
      "x": "0.540108308",
      "y": "1.435191937"
    },
    {
      "turn": "-0.337707806",
      "x": "0.280824915",
      "y": "1.425191366"
    },
    {
      "turn": "-0.337707806",
      "x": "1.279756130",
      "y": "1.403001680"
    },
    {
      "turn": "0.200541705",
      "x": "0.957721470",
      "y": "1.381542921"
    },
    {
      "turn": "-0.337707806",
      "x": "0.733427752",
      "y": "1.287812893"
    },
    {
      "turn": "0.200541705",
      "x": "1.611799267",
      "y": "1.238889923"
    },
    {
      "turn": "0.200541705",
      "x": "0.249850641",
      "y": "1.184082294"
    },
    {
      "turn": "0.200541705",
      "x": "1.248781856",
      "y": "1.161892609"
    },
    {
      "turn": "-0.337707806",
      "x": "1.805118710",
      "y": "1.091510879"
    },
    {
      "turn": "-0.337707806",
      "x": "1.024488138",
      "y": "1.068162581"
    },
    {
      "turn": "0.200541705",
      "x": "0.702453478",
      "y": "1.046703822"
    },
    {
      "turn": "-0.337707806",
      "x": "0.443170085",
      "y": "1.036703250"
    },
    {
      "turn": "-0.337707806",
      "x": "1.442101300",
      "y": "1.014513565"
    },
    {
      "turn": "0.200541705",
      "x": "1.774144436",
      "y": "0.850401807"
    },
    {
      "turn": "0.097516661",
      "x": "0.160083974",
      "y": "0.834615666"
    },
    {
      "turn": "0.200541705",
      "x": "0.993513864",
      "y": "0.827053510"
    },
    {
      "turn": "0.200541705",
      "x": "1.411127026",
      "y": "0.773404494"
    },
    {
      "turn": "0.081086445",
      "x": "0.581745452",
      "y": "0.709595637"
    },
    {
      "turn": "-0.337707806",
      "x": "1.186833308",
      "y": "0.679674466"
    },
    {
      "turn": "-0.454258290",
      "x": "0.335778629",
      "y": "0.665315059"
    },
    {
      "turn": "-0.337707806",
      "x": "1.604446470",
      "y": "0.626025450"
    },
    {
      "turn": "-0.337707806",
      "x": "0.824698912",
      "y": "0.552267139"
    },
    {
      "turn": "0.200541705",
      "x": "1.134531252",
      "y": "0.441305286"
    },
    {
      "turn": "0.200541705",
      "x": "1.552144414",
      "y": "0.387656270"
    },
    {
      "turn": "0.473394652",
      "x": "0.457396572",
      "y": "0.337887904"
    },
    {
      "turn": "0.200541705",
      "x": "0.793724638",
      "y": "0.311158068"
    },
    {
      "turn": "-0.337707806",
      "x": "1.327850696",
      "y": "0.293926242"
    },
    {
      "turn": "-0.337707806",
      "x": "0.987044082",
      "y": "0.163779024"
    }
  ],
  "radius": "0.243090496"
}

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

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