## Problem С. Commentator problem

Let*R*be the distance from point А to a circle with center О and radius

*r*. From this point the circle is observed at the angle .

So, the three stadiums are observed at the same angle if

*R*_{1}/*r*_{1}=*R*_{2}/*r*_{2}=*R*_{3}/*r*_{3}.Take two different points A, B. The set of points C that

*AC*/

*BC*=

*const*is either a line (perpendicular bisector of AB) or a circle with center somewhere on the line AB. This circle is easy to find. It contains two points that lie on AB and satisfy

*AC*/

*BC*condition.