is uniquely identified as a triangle having its three angles in the ratio 1 : 1 : 3 (36°, 36°, 108°). Its base angles are 36° each, which is the same as the apex of the golden triangle. Bisections By bisecting one of its base angles, a golden triangle can be subdivided into a golden triangle and a golden gnomon. By trisecting its apex angle, a golden gnomon can be subdivided into a golden triangle and a golden gnomon. A golden gnomon and a golden triangle with their equal sides matching each other in length, are also referred to as the obtuse and acute Robinson triangles. Tilings A golden triangle and two golden gnomons tile a regular pentagon. These isosceles triangles can be used to produce Penrose tilings. Penrose tiles are made from kites and darts. A kite is made from two golden triangles, and a dart is made from two gnomons. See also Golden rectangle Golden rhombus Kepler triangle Kimberling's golden triangle Lute of Pythagoras Pentagram Golden triangle (composition) References External links Robinson triangles at Tilings Encyclopedia Golden triangle according to Euclid The extraordinary reciprocity of golden triangles at Tartapelago by Giorgio Pietrocola Types of triangles Golden ratio