P85 · Packing and covering · Classic

Squares in an equilateral triangle

VERIFIED CONSTRUCTIONVERIFIED CONSTRUCTION
n = 6Current record · open

Pack n unit-side squares into a equilateral triangle. Contact is allowed; interiors cannot overlap. Minimise the container triangle side.

Formal definition

  • ContainerThe editor and certificate normalize to the equilateral triangle with vertices (0,0), (1,0), (1/2,√3/2). This is a coordinate convention only; scores use the literature's unit-piece scale. Boundary contact is allowed.
  • SubmissionSubmit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4.
  • ConstraintsExactly n congruent shapes lie wholly in the container with pairwise disjoint interiors. Polygon rotations are independent, not limited to quarter turns.
  • PrecisionInput decimals are exact rationals; regular-polygon vertices are algebraic, not rounded templates. Feasibility has no floating-point tolerance. A finite-decimal certificate is not a continuous optimality proof.
  • Objectivecontainer triangle side = 1/(2 sin(pi/4) r), smaller is better. Pages, leaderboards and literature share these units; conversion is automatic.

Getting a feel for it

Source and certificate

External targets are converted with their printed precision; decimal coordinate certificates are separate. Reconstruction loss never lowers the literature target, and a source construction is not automatically an optimality proof.

Source
ONE LEADERBOARD PER n

Current best solutions by n

Each n is an independent record with a page of its own. Open any of them to inspect the current construction, then challenge it.

Discussion (0) ↓
n3
CURRENT RECORD3.23205083best known 3.232
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n4
CURRENT RECORD4.154700559best known 4.154
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n5
CURRENT RECORD4.309401093best known 4.309
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n6
CURRENT RECORD4.30940112best known 4.309
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n7
CURRENT RECORD5.154700559best known 5.154
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n8
CURRENT RECORD5.301221349best known 5.301
Matches the best known
Answer sourceDavid W. Cantrell
Solution methodPublished reference construction
n9
CURRENT RECORD5.309401136best known 5.309
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n10
CURRENT RECORD5.464101639best known 5.464
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n11
CURRENT RECORD6.154700595best known 6.154
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n12
CURRENT RECORD6.301221383best known 6.301
Matches the best known
Answer sourceDavid W. Cantrell
Solution methodPublished reference construction
n13
CURRENT RECORD6.309401135best known 6.309
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n14
CURRENT RECORD6.464101719best known 6.464
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n15
CURRENT RECORD6.464101719best known 6.464
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n16
CURRENT RECORD7.15470061best known 7.154
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n17
CURRENT RECORD7.301221441best known 7.301
Matches the best known
Answer sourceDavid W. Cantrell
Solution methodPublished reference construction
n18
CURRENT RECORD7.309401143best known 7.309
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n19
CURRENT RECORD7.464101733best known 7.464
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n20
CURRENT RECORD7.616954284best known 7.61695
Matches the best known
Answer sourceHaowei Lin
Solution methodPublished reference construction
n21
CURRENT RECORD7.618802248best known 7.618
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n22
CURRENT RECORD8.15470064best known 8.15470
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n23
CURRENT RECORD8.301221414best known 8.301
Matches the best known
Answer sourceDavid W. Cantrell
Solution methodPublished reference construction
n24
CURRENT RECORD8.309401166best known 8.309
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n25
CURRENT RECORD8.464101687best known 8.464
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n26
CURRENT RECORD8.618802344best known 8.618
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n27
CURRENT RECORD8.618802344best known 8.618
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n28
CURRENT RECORD8.773502876best known 8.773
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n29
CURRENT RECORD9.154700661best known 9.154
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n30
CURRENT RECORD9.301221507best known 9.301
Matches the best known
Answer sourceDavid W. Cantrell
Solution methodPublished reference construction
n31
CURRENT RECORD9.30940126best known 9.309
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n32
CURRENT RECORD9.464101702best known 9.464
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n33
CURRENT RECORD9.618802281best known 9.618
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n34
CURRENT RECORD9.618802281best known 9.618
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n35
CURRENT RECORD9.773502816best known 9.773
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n36
CURRENT RECORD9.773502816best known 9.773
Matches the best known
Answer sourceErich Friedman
Solution methodPublished reference construction
n37
CURRENT RECORD29.168155016best known 10.15299
Hard
Record holderFounding benchmark
Solution methodHuman
n38
CURRENT RECORD29.168155016best known 10.304
Hard
Record holderFounding benchmark
Solution methodHuman
n39
CURRENT RECORD10.309401268best known 10.30940
Matches the best known
Answer sourceBhavithran Ananthan
Solution methodPublished reference construction
n40
CURRENT RECORD10.464101789best known 10.46410
Matches the best known
Answer sourceBhavithran Ananthan
Solution methodPublished reference construction

Data and citation

Every sub-problem in this family — authoritative scores, proof status, coordinates and sources — lives at the stable address below, published under CC BY 4.0. Scores move as records fall, so cite the generatedAt timestamp the file carries.

GET https://minmaxarena.com/data/squares-in-triangle.json

Cite the frozen 2026-08 edition: records move, a frozen edition never does, so the citation is still checkable years later.

GET https://minmaxarena.com/data/editions/2026-08/squares-in-triangle.json
BibTeX (click to copy)
@misc{minmaxarena-squares-in-triangle-2026-08,
  title  = {{Squares in an equilateral triangle} (P85)},
  author = {{MinMax Arena}},
  year   = {2026},
  note   = {Machine-verified records, 2026-08 edition},
  url    = {https://minmaxarena.com/data/editions/2026-08/squares-in-triangle.json},
  license = {CC BY 4.0}
}
DISCUSSION

Discussion

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