Talk:Apothem

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[edit] Contradiction

  1. "Regular polygons are the only polygons that have apothems. Because of this, all the apothems in a polygon will be congruent and have the same length."
  2. "A triangle has four centers, circumcenter, incenter, centroid, and orthocenter. The center that is used to find the apothem is the incenter."

1 renders 2 a null statement, since for an equilateral triangle all centres coincide. I can therefore make out only that either:

  • whoever wrote 1 was considering a triangle not to count as a polygon, which contradicts the view taken at Polygon, and that the definition of apothem treats triangles specially
  • somebody just didn't know what he/she was talking about

What is correct? ISTM the real definition of apothem should be a generalisation of both statements: for any polygon that has an inscribed circle (to which every side is a tangent), a radius of this circle that meets a side of the polygon (and is therefore perpendicular to it). But can anybody find a good source on the term? (MathWorld contradicts itself too - it defines the apothem of a general regular polygon as the same as the inradius, which it defines only for general triangles and polyhedra.)

On the basis of this definition, all apothems of a given polygon are the same length not for the reason given in 1, but because they are radii of the circle. What was the writer of 1 (mis)using congruent to mean, anyway? -- Smjg (talk) 11:46, 12 February 2009 (UTC)

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