Let $ABC$ be an isosceles triangle such that $AB=AC$. Find angles of triangle $ABC$ if $\frac{AB}{BC}=1+2\cos{\frac{2\pi}{7}}$
Problem
Source: Regional Olympiad - Federation of Bosnia and Herzegovina 2017
Tags: geometry, isosceles, angles, cosine
Source: Regional Olympiad - Federation of Bosnia and Herzegovina 2017
Tags: geometry, isosceles, angles, cosine
Let $ABC$ be an isosceles triangle such that $AB=AC$. Find angles of triangle $ABC$ if $\frac{AB}{BC}=1+2\cos{\frac{2\pi}{7}}$