# How to set font, line spacing and header/footer margins?

I need to write some text for my university and I figured I should use LaTeX to get familiar with the system. I've read some basic tutorials etc, but they didn't help me with the following:

There are some rather strict requirements on how the text must be formatted and on the page layout:
* Text must have font size 12pt and font 'Arial'
* Spacing between lines must be 1.5x
* Left margin must be 3cm, right margin must be 2cm
* The header must have 1.25 cm distance from the top
* The footer must have 1.25 cm distance from the bottom

This is what I got right now:

% Set font size
\documentclass[12pt]{report}

% Set paper size and margins. Seems to work correctly.
\usepackage[a4paper,left=3cm,right=2cm,top=2.5cm,bottom=2.5cm]{geometry}

% Needed for line spacing
\usepackage{setspace}

% For testing, visualizes margins.
\usepackage{showframe}

\begin{document}

% Set line spacing to 1.5
\begin{onehalfspace}

Content.\\
Next line.

\end{onehalfspace}

\end{document}


So, here are my questions:
1. I haven't found any way to set the font to 'Arial'. I would guess that it is a simple command. How is it done?
2. Is there a better way to set the line spacing than what I have done?
3. How do I change the distance between header and top, or footer and bottom?

I hope those are not too many questions for one topic. Sorry if some of those seem obvious, I really tried solving them myself. Maybe I just don't know the right sites for things like that yet.

Thank you very much for your help :)

• This requirements are Windows(MS-Word) based and should be taken with care. 12pt for Word isn't 12pt in LaTeX. Basically, unless xelatex (or lualatex) is used, there is no Arial font for TeX, but the font by the helvet package resembles Arial (somewhat) – user31729 Feb 5 '16 at 13:01
• The top/bottom margins should take headheight into account – user31729 Feb 5 '16 at 13:06
• Oh, I did not know that the sizes are not the same... I think I am using pdflatex right now (I do not really understand things here, so maybe that falls into a whole other category). And I am on Win10, got TexMaker + MiKTeX 2.9 installed. – Apfelmännchen Feb 5 '16 at 14:22