Filling a region between circles using Tkz-Euclide

Question

I am trying to fill the region inside the circle centered on C but outside the circle centered on B using TikZ or Tkz-Euclide but I am unable to do so. I just got help on a similar question and I tried to use it to my advantage, but to no avail.

\documentclass[10pt]{scrartcl}
\usepackage{tkz-euclide}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}
\tkzDefPoints{0/0/A, 1/0/B, 2/0/C, 3/0/D, 4/0/E, 5/0/F, 6/0/G}
\tkzDrawCircleR
\tkzDrawCircleR
\tkzDrawCircleR
\tkzDrawPoints(A,B,C,D,E,F,G)
\tkzDrawSegment(A,G)
\tkzLabelPointsbelow
\tkzLabelPointsleft
\tkzLabelPointsright
\tkzLabelPointsbelow right
\filldraw[color=gray, opacity=0.5]
(E) arc (0:180:2cm);
\end{tikzpicture}
\end{document}

Answer 1

I could write another comment, but maybe it is clearer when I use an answer for this because this way I can add a screen shot. As I said in the comments, you can omit most of the coordinates. The reason for writing an answer is that I'd like to encourage you using the backgrounds library for that. I assume you added opacity because you did not want to get rid of the nodes. If that's the case, you may put the fills on the background. That way you can use also full colors. This also applied to the nice solution proposed by J. Leon V. As you see, the labels do not get blurred out.

\documentclass[10pt]{scrartcl}

\usepackage{tikz}
\usepackage{tkz-euclide}
\usetikzlibrary{calc,backgrounds}

\begin{document}

\begin{tikzpicture}
\tkzDefPoints{0/0/A, 1/0/B, 2/0/C, 3/0/D, 4/0/E, 5/0/F, 6/0/G}
\tkzDrawCircle[R](B,1cm)
\tkzDrawCircle[R](C,2cm)
\tkzDrawCircle[R](D,3cm)
\tkzDrawPoints(A,B,C,D,E,F,G)
\tkzDrawSegment(A,G)
\tkzLabelPoints[below](B,D,F)
\tkzLabelPoints[left](A)
\tkzLabelPoints[right](G)
\tkzLabelPoints[below right](C,E)
\begin{scope}[on background layer]
\fill[gray!50] (A) arc(-180:180:2cm) arc(180:-180:1cm) --cycle;
\fill[blue](A) arc(-180:180:3cm) arc(180:-180:2cm) --cycle;
\end{scope}
\end{tikzpicture}
\end{document}

Here are examples of just upper and lower halfs.

\documentclass[tikz,border=3.14mm]{standalone}
\usepackage{tkz-euclide}
\usetikzlibrary{calc,backgrounds}

\begin{document}
\begin{tikzpicture}
\tkzDefPoints{0/0/A, 1/0/B, 2/0/C, 3/0/D, 4/0/E, 5/0/F, 6/0/G}
\tkzDrawCircle[R](B,1cm)
\tkzDrawCircle[R](C,2cm)
\tkzDrawCircle[R](D,3cm)
\tkzDrawPoints(A,B,C,D,E,F,G)
\tkzDrawSegment(A,G)
\tkzLabelPoints[below](B,D,F)
\tkzLabelPoints[left](A)
\tkzLabelPoints[right](G)
\tkzLabelPoints[below right](C,E)
\begin{scope}[on background layer]
\fill[gray!50] (A) arc(180:00:2cm) -- (C) arc(00:180:1cm) --cycle;
\fill[blue] (A) arc(180:360:3cm) --(E) arc(00:-180:2cm)  --cycle;
\end{scope}
\end{tikzpicture}
\end{document}

Answer 2

I managed to do it. Here's the result:

\documentclass[10pt]{scrartcl}

\usepackage{tikz}
\usepackage{tkz-euclide}
\usetikzlibrary{calc}

\begin{document}

\begin{tikzpicture}
\tkzDefPoints{0/0/A, 1/0/B, 2/0/C, 3/0/D, 4/0/E, 5/0/F, 6/0/G}
\tkzDrawCircle[R](B,1cm)
\tkzDrawCircle[R](C,2cm)
\tkzDrawCircle[R](D,3cm)
\tkzDrawSegment(A,G)
\tkzLabelPoints[below](B,D,F)
\tkzLabelPoints[left](A)
\tkzLabelPoints[right](G)
\tkzLabelPoints[below right](C,E)
\filldraw[color=gray, opacity=0.5]
(E) arc (0:180:2cm) --
(A) arc (180:-180:1cm) --
(A) arc (-180:0:2cm) -- cycle;
\tkzDrawPoints(A,B,C,D,E,F,G)
\end{tikzpicture}

\end{document}

Answer 3

It is possible to fill this area with the even odd rule. I have already explained this rule in this answer. Here, the path is composed of the succession of 3 circles:

\draw[fill=green, even odd rule] (D) circle(3cm)(B) circle (1cm) (C) circle (2cm);

Here, the area to color is an even area that with the even odd rule is not colored. In order for it to be colored with the even odd rule, this area would have to be odd. To do this, simply add the largest circle (center D) one more time to the path composed of the other three.

\draw[fill=green, even odd rule] (D) circle(3cm)(B) circle (1cm) (C) circle (2cm) (D) circle(3cm);

Full code:

\documentclass[10pt]{scrartcl}
\usepackage{tikz}
\usepackage{tkz-euclide}
\usetikzlibrary{calc,backgrounds}

\begin{document}
\begin{tikzpicture}
\tkzDefPoints{0/0/A, 1/0/B, 2/0/C, 3/0/D, 4/0/E, 5/0/F, 6/0/G}
\draw[fill=green, even odd rule] (D) circle(3cm)(B) circle (1cm) (C) circle (2cm) (D) circle(3cm);
\tkzDrawPoints(A,B,C,D,E,F,G)
\tkzDrawSegment(A,G)
\tkzLabelPoints[below](B,D,F)
\tkzLabelPoints[left](A)
\tkzLabelPoints[right](G)
\tkzLabelPoints[below right](C,E)
\end{tikzpicture}
\end{document}

Result by drawing the center circle D twice:

Output by default (3 circles):

Translated with www.DeepL.com/Translator

Answer 4

\documentclass[10pt]{scrartcl} 
\usepackage{tkz-euclide}

\begin{document}

\begin{tikzpicture}
\tkzDefPoints{0/0/A, 1/0/B, 2/0/C, 3/0/D, 4/0/E, 5/0/F, 6/0/G}
\tkzFillCircle[blue!20](C,E)
\tkzFillCircle[white](B,C)
\tkzDrawCircle[R](B,1)
\tkzDrawCircle[R](C,2)
\tkzDrawCircle[R](D,3)
\tkzDrawPoints(A,B,C,D,E,F,G)
\tkzDrawSegment(A,G)
\tkzLabelPoints[below](B,D,F)
\tkzLabelPoints[left](A)
\tkzLabelPoints[right](G)
\tkzLabelPoints[below right](C,E)
\end{tikzpicture}
\end{document}