Mazėtis, E. and Melničenko, G. (2013) “A rational sine and cosine of the angles of a triangle”, Lietuvos matematikos rinkinys, 54(B), pp. 151–154. doi:10.15388/LMR.B.2013.28.
A rational sine and cosine of the angles of a triangle
Abstract
The article deals with triangles whose sines and cosines of the angles are the rational numbers. We prove that these triangles are similar to Pythagorean or Heronian triangles, and vice versa.