Integer triangle side of the formula are integers it follows that all integer triangles must have an integer value of "16T" and "T" will be rational. By the law of cosines, every angle of an integer triangle has a rational cosine. If the angles of any triangle form an arithmetic progression then one of its angles must be 60°. For integer triangles the remaining angles must also have rational cosines and a method of generating such triangles is given below. However, apart from the trivial case of an equilateral triangle there are no integer triangles whose angles form either a geometric or
Equilateral pentagon are sufficient to determine a convex equilateral pentagon. Each circle's center is one of four vertices of the pentagon. The remaining vertex is determined by one of the intersection points of the first and the last circle of the chain. It is possible to describe any convex equilateral pentagon with only two angles α and β with α ≥ β provided the fourth angle (δ) is the smallest of the rest of the angles. Thus the general equilateral pentagon can be regarded as a bivariate function "f(α, β)" where the rest of the angles can be obtained by using trigonometric