$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
9.17
\begin{equation} \begin{gathered}\label{equation:two-out-of-three-for-orthogonal} \xymatrix@R =50pt@C=50pt{ & B \ar [dr]^{ f'' } & \\ A \ar [ur]^{f'} \ar [rr]^{f} & & C. } \end{gathered} \end{equation}