This question may seem repetitive to many, but as I am very new to Latex, even after reading many posts, could not get to draw what I wanted, so asking.

I want to draw as the following.

I have written the following code, Please help further.

```
\documentclass[11pt, oneside]{article}
\usepackage{geometry} % See geometry.pdf to learn the layout options. There are lots.
\geometry{letterpaper} % ... or a4paper or a5paper or ...
\geometry{landscape}
\usepackage{tikz} % TeX will automatically convert eps --> pdf in pdflatex
\usepackage{amssymb}
\usepackage{textcomp}
\usepackage{gensymb}
\usepackage{tkz-euclide}
\usetikzlibrary{shapes.geometric}
\usetikzlibrary{calc}
\usepackage{graphicx}
\usetikzlibrary{plotmarks}
\title{}
\author{}
\begin{document}
\begin{tikzpicture}
\draw (0,0) circle(2) node [left] {P};
\draw (3.5,0) circle(1.5) node [below] {Q};
\draw (0,0) -- (14,0) node [right] {O};
\newcommand*{\Radius}{2cm}%
\coordinate (Origin) at (0,0);
\coordinate (O) at (14,0);% External point
\tkzDrawCircle[R](Origin,\Radius)
\tkzTangent[from with R= O](Origin,\Radius) \tkzGetPoints{R}{I}
\tkzDrawSegments[ultra thick](O,R)% First tangent
\tkzDrawSegments[ultra thick](O,I)% Second tangent
\end{tikzpicture}
\end{document}
```

## Best Answer

I give my personal answer because It's preferable to avoid to mix syntaxes ( tikz and euclide ) and I added some remarks. I take big parts from hpesoj626's answer.

Firstly, I prefer to use several parts in my code, I created

tkz-euclideto do this: definition, calculations, drawings and labels. If you study tikz enough, you will be able to use only tikz and to puttkz-euclidein the trash.Remarks about definitions`coordinate`

here from tikz but if you use another system of coordinates from tkz then you can go down some complications.`\pgfmathsetmacro`

is more`tikzien`

but you need to add the unity afterRemarks about calculations: none it's fineRemarks about drawings :tkz-euclidemacros come by pair like`\tkzDrawSegment`

and`\tkzDrawSegments`

. The second is to draw several objects with the same options but if you need specific options, then you need to use the first form.`add`

. I added totkz-euclidethe possibility to use tikz option but I added somme specific option that I created. You can use`add = n and m`

to extend a line (n and m are a percent of the length of the line. I prefer this possibility because it's easy to add half of a line or to double the line.Remarks about labels :The same remarks about the pair of macros. You can add labels with general options or with specific ones.

Conclusiontkz-euclideis useful only if you need to draw several pictures and if you want to write rapidly your code but for one picture, I think it's preferable to study tikz. Withtkz-euclideyou need to know some options from tikz.So a

tkz-euclidesolution is