How to make document custom page dimensions?

Hope the code is self explanatory.

For first,

\documentclass{article}
\usepackage{blindtext}
\usepackage[paperheight=10.75in,paperwidth=8.25in,margin=1in,heightrounded,showframe]{geometry}
\begin{document}

\Blinddocument

\end{document}

and the second:

\documentclass{article}
\usepackage{blindtext}
\usepackage[paperheight=9in,paperwidth=6in,top=1in,bottom=1in,right=1in,left=1in,heightrounded,showframe]{geometry}
\begin{document}

\Blinddocument

\end{document}