MathDB
Chisinau MO p94 1975 R1 IX locus of vertex of equilateral

Source:

March 16, 2021
geometryLocus

Problem Statement

A straight line \ell and a point AA outside of it are given on the plane. Find the locus of the vertices CC of the equilateral triangle ABCABC, the vertex BB of which lies on the straight line \ell.