change to letter size on teXnicCenter & MikTex

Question

How come TeXicCenter and MiKTeX always generate an A4 size pdf paper?

I reinstalled both MiKTeX and TeXicCenter and I made sure that I selected "Letter" to be my default paper size. Nothing changes.

Answer 1

Here is what worked for me, regardless of the documentclass or other packages used.

Right after \begin{document} I put these two lines:

\setlength{\pdfpagewidth}{8.5in}

\setlength{\pdfpageheight}{11in}