The
homothety of point \(M\) with center \(O\) and scale factor \(\textcolor{olive}{k}\) is the point \(M'\) such that \(\overrightarrow{OM'}=\textcolor{olive}{k}\overrightarrow{OM}\). In particular, the points \(O\), \(M\), and \(M'\) lie on the same line, and the distance from \(O\) to \(M'\) is \(|\textcolor{olive}{k}|\) times the distance from \(O\) to \(M\).

\(\dfrac{\textcolor{colorprop}{OM'}}{\textcolor{colordef}{OM}}=|\textcolor{olive}{k}|\)