Skip to main content\(\newcommand{\N}{\mathbb N} \newcommand{\Z}{\mathbb Z} \newcommand{\Q}{\mathbb Q} \newcommand{\R}{\mathbb R}
\newcommand{\lt}{<}
\newcommand{\gt}{>}
\newcommand{\amp}{&}
\definecolor{fillinmathshade}{gray}{0.9}
\newcommand{\fillinmath}[1]{\mathchoice{\colorbox{fillinmathshade}{$\displaystyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\textstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptscriptstyle\phantom{\,#1\,}$}}}
\)
Instructions.
Use this interactive tool to follow the geometric construction steps for finding a center of rotation.
Click the checkboxes at the bottom left in order (from 1 to 5). Notice how the perpendicular bisector of the line joining corresponding points (
\(AA'\)) and the perpendicular bisector of (
\(BB'\)) perfectly intersect. That exact point of intersection is your centre of rotation!