added circle-diameter-radius image

tikz/circle-diameter-radius/Makefile

@@ -0,0 +1,35 @@
+SOURCE = circle-diameter-radius
+DELAY = 80
+DENSITY = 300
+WIDTH = 512
+
+make:
+	pdflatex $(SOURCE).tex -output-format=pdf
+	make clean
+
+clean:
+	rm -rf  $(TARGET) *.class *.html *.log *.aux *.data *.gnuplot
+
+gif:
+	pdfcrop $(SOURCE).pdf
+	convert -verbose -delay $(DELAY) -loop 0 -density $(DENSITY) $(SOURCE)-crop.pdf $(SOURCE).gif
+	make clean
+
+png:
+	make
+	make svg
+	inkscape $(SOURCE).svg -w $(WIDTH) --export-png=$(SOURCE).png
+
+transparentGif:
+	convert $(SOURCE).pdf -transparent white result.gif
+	make clean
+
+svg:
+	make
+	#inkscape $(SOURCE).pdf --export-plain-svg=$(SOURCE).svg
+	pdf2svg $(SOURCE).pdf $(SOURCE).svg
+	# Necessary, as pdf2svg does not always create valid svgs:
+	inkscape $(SOURCE).svg --export-plain-svg=$(SOURCE).svg
+	rsvg-convert -a -w $(WIDTH) -f svg $(SOURCE).svg -o $(SOURCE)2.svg
+	inkscape $(SOURCE)2.svg --export-plain-svg=$(SOURCE).svg
+	rm $(SOURCE)2.svg

tikz/circle-diameter-radius/Readme.md

@@ -0,0 +1,3 @@
+Compiled example
+----------------
+![Example](circle-diameter-radius.png)

tikz/circle-diameter-radius/circle-diameter-radius.tex

@@ -0,0 +1,25 @@
+\documentclass[varwidth=true, border=2pt]{standalone}
+\usepackage{tikz}
+\usetikzlibrary{shapes, calc, shapes, arrows} 
+\usepackage{amsmath,amssymb}
+
+\usepackage{xcolor}
+\definecolor{xvectorcolor}{HTML}{77933C}
+
+\begin{document}
+\begin{tikzpicture}
+    \newcommand{\R}{1.4}
+    \path (240:\R) coordinate (A);
+    \path ( 60:\R) coordinate (B);
+    \path ( 0:\R) coordinate (C);
+    \draw[green,fill=gray!10] (0,0) circle (\R);
+
+    \draw[red] (0,0) -- (C);
+    \path[red] ( 0:\R/2) node [below]{$r$};
+    \draw[blue] (A) -- (B);
+    \path[blue] (240:\R/2) node [below]{$d$};
+    \draw[green] (0,0) circle (\R);
+    \path[green] (135:\R*1.2) node {$c$};
+    \draw[black] (0,0) node [left] {$M$};
+\end{tikzpicture}
+\end{document}