# Figures numbering in arabic while chapters in roman

I have an issue with the numbering of the figures. I have my chapters numbered in Roman thanks to the command \renewcommand{\thechapter}{\Roman{chapter}} (Chapter I, Chapter II etc.). Therefore, I would like the figures to be numbered by chapters with arabic numbers like Figure 1.2 for the second figure of Chapter I.

Do you have any idea ?

Thanks, Pierre

• \renewcommand{\thefigure}{\arabic{chapter}.\arabic{figure}} in the preamble. Do you really want an arabic chapter number for the figure? – user31729 Oct 25 '15 at 13:28
• Hi @ChristianHupfer, it works perfectly well (ps you just have forgotten a \ before thefigure – PMC1234 Oct 25 '15 at 13:32
• I corrected it some minutes ago :-P – user31729 Oct 25 '15 at 13:33

The figure environment uses the figure counter, which is defined to be reset when the chapter is increased (e.g. each time a new chapter is begun.)

This will also lead to use the chapter counter prefix (here Roman) in the figure counter output, i.e. \thefigure is \thechapter.\arabic{figure} most likely.

If this is not wanted, the \thefigure command must be redefined, say, to

\renewcommand{\thefigure}{\arabic{chapter}.\arabic{figure}}


Here is minimal example:

\documentclass{book}

\renewcommand{\thechapter}{\Roman{chapter}}
\renewcommand{\thefigure}{\arabic{chapter}.\arabic{figure}}

\begin{document}
\tableofcontents
\listoffigures
\chapter{First}

\begin{figure}
\caption{A dummy figure}
\end{figure}

\begin{figure}
\caption{Another dummy figure}
\end{figure}

\chapter{Second}

\begin{figure}
\caption{A dummy figure}
\end{figure}

\begin{figure}
\caption{Another dummy figure}
\end{figure}

\end{document}