I'm compiling this simple tex file. 

```
\newcommand\sheetwidth{373.33333333mm}
\newcommand\sheetheight{210mm}
\documentclass[paper=\sheetwidth:\sheetheight]{scrartcl}
\usepackage[ includeheadfoot,  top=8.0mm,  bottom=3.5mm,
left=15.0mm, right=15.0mm, headsep=1.5mm, footskip=8.5mm]{geometry}

\begin{document}
This is my test
\end{document}

```

However, when I compile it I get the wrong output. The width should be larger than the height. This is what I see:

[![enter image description here](https://i.stack.imgur.com/HW6HY.png)](https://i.stack.imgur.com/HW6HY.png)

I'm working in windows and compiling the tex document using pdflatex (compiling with lualatex gives the same output). 
I've already tried to re-install miktex but this doesn't solve the problem.