A rational cotangents of the angles of a triangle
Edmundas Mazėtis
Vilniaus universitetas
Grigorijus Melničenko
Lietuvos edukologijos universitetas
Published 2014-12-20


Heronian triangles
pseudo Heronian triangles
integer lattice

How to Cite

Mazėtis E. and Melničenko G. (2014) “A rational cotangents of the angles of a triangle”, Lietuvos matematikos rinkinys, 55(B), pp. 84–89. doi: 10.15388/LMR.B.2014.16.


We investigate how rational values cotangents angles of a triangle influence of its properties. The main result: cotangents of any two angles of a triangle are rational then, and only then, when a triangle similar to a triangle whose squares of sides are integer and twice the area is an integer.

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