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PROJECT EULER · #0264

Triangle Centres

Statement only · SolvedOriginal problem ↗

Consider all the triangles having:

  • All their vertices on lattice pointsInteger coordinates.
  • CircumcentreCentre of the circumscribed circle at the origin O.
  • OrthocentrePoint where the three altitudes meet at the point H(5,0).

There are nine such triangles having a perimeter 50.
Listed and shown in ascending order of their perimeter, they are:

A(4,3), B(5,0), C(4,3)
A(4,3), B(5,0), C(4,3)
A(3,4), B(5,0), C(3,4)


A(3,4), B(5,0), C(3,4)
A(0,5), B(5,0), C(0,5)
A(1,8), B(8,1), C(4,7)


A(8,1), B(1,8), C(4,7)
A(2,9), B(9,2), C(6,7)
A(9,2), B(2,9), C(6,7)
0264_TriangleCentres.gif

The sum of their perimeters, rounded to four decimal places, is 291.0089.

Find all such triangles with a perimeter 105.
Enter as your answer the sum of their perimeters rounded to four decimal places.

Write-up coming later

The complete problem is available here. An approach, code, and answer will be added later.