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Here are the coordinates of nine points. It is possible to draw a triangle so that the shortest distance from each point to the triangle is at most one unit.

$(0, 0)$
$(8, 2)$
$(7, 8)$
$(170, 180)$
$(340, 360)$
$(2001, 1000)$
$(1500, 750)$
$(3000, 2000)$
$(4002, 2000)$

Can you find a suitable triangle? Is there more than one possibility?


Given three points, it is always possible to draw different triangles with edges passing through those three points - here are some examples of triangles going through the same three points:
Triangles through 3 points
Can you convince yourself that there are always infinitely many such triangles?


Here are some examples of different triangles going through the same set of four points:
triangles through four dots
Is it always possible to draw triangles through a set of four points, whatever their position?
Investigate some examples and explain your findings.

What happens when we try to draw triangles through five points?



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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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