Use the tikz package to plot two overlapping, semi-transparent circles with labels

I need to produce something similar to this with latex

I am not familiar at all with the tikz package. However I was able to find a code that I think could be adapted to fit with my needs:

\begin{tikzpicture}[scale=0.75][thick]
\draw (0,0) circle (2cm);
\draw (3,-1) circle (2.5cm);
\draw (0,0) node {A};
\draw (3.2,-1) node {B};
\draw [clip](0,0) circle (2cm);
\fill[yellow] (3,-1) circle (2.5cm);
\end{tikzpicture}


It produces this figure:

Does anybody have an idea of how I could adapt the above code to get what I want?

• The source code was found at latex-community.org/forum/viewtopic.php?f=45&t=9937 May 31 '16 at 11:38
• Welcome to TeX.SX!! It is better to post a full minimal working example. It's better to include the full code in he question rather than posting a link. A LaTeX MWE should start with a \documentclass command, have a minimal preamble and then \begin{document}...\end{document}. The code should compile and be as small as possible to demonstrate your problem. This makes it much easier for people to help you --- and much more likely that they will!
– user30471
May 31 '16 at 12:15

No need to clip; you can use fill opacity. Start with:

\documentclass[margin=10pt]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[
thick]
\draw [fill=cyan, fill opacity=0.5] (0,0) circle (2cm);
\draw [fill=orange, fill opacity=0.5] (3,-1) circle (2.5cm);
\end{tikzpicture}
\end{document}


and the rest of the thing is a bit of geometry and maybe the intersections library:

\documentclass[margin=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows,positioning,calc,intersections}
\begin{document}
\begin{tikzpicture}[
thick]
\draw [fill=cyan, fill opacity=0.5, name path=c1] (0,0) circle (2cm);
\draw [fill=orange, fill opacity=0.5, name path=c2] (3,-1) circle (2.5cm);
\draw (0,0) ++(120:2cm) -- ++(120:2.2cm) node [fill=white,inner sep=5pt](a){a};
\draw (3, -1) ++(30:2.5cm) -- ++(30:2.6cm) node [fill=white,inner sep=5pt](b){b};
\path [name intersections={of=c1 and c2,by=cs}];
\draw (cs) -- ++(.5,1) node [fill=white,inner sep=5pt](c){c};
\end{tikzpicture}
\end{document}


...I leave the rectangles in the legend as an exercise.