\begin{center}
	\begin{tikzpicture}
		\tkzDefPoint(0,0){A} \tkzDefPoint(7,0){B} \tkzDefPoint(7/2+3,0){vH}
		\tkzLabelLine[below left](A,B){$a$} \tkzCompass(A,B)
		\tkzInterCC(A,B)(B,A) \tkzGetPoints{P1}{P2}
		\tkzCompass(A,P1) \tkzCompass(B,P1) \tkzCompass(A,P2)\tkzCompass(B,P2)
		\tkzDrawLine(P1,P2) \tkzInterLL(P1,P2)(A,B) \tkzGetPoint{M}
		\tkzInterLC(P1,P2)(M,vH) \tkzGetPoints{V}{VUSELESS} \tkzCompass(M,V)
		\tkzInterLC(P1,P2)(V,M) \tkzGetPoints{VX}{MAGAIN} \tkzCompass(V,VX)
		\tkzInterCC(M,VX)(VX,M) \tkzGetPoints{V1}{V2}
		\tkzCompass(M,V1)\tkzCompass(M,V2)\tkzCompass(VX,V1)\tkzCompass(VX,V2)
		\tkzDrawLine(V1,V2) \tkzInterLL(P1,P2)(V1,V2) \tkzGetPoint{M2}
		\tkzInterLC(A,B)(A,M) \tkzGetPoints{MX}{MAGAIN} \tkzCompass(A,MX)
		\tkzInterCC(MX,M)(M,MX) \tkzGetPoints{A1}{A2}
		\tkzDrawLine(A1,A2) \tkzInterLL(A1,A2)(V1,V2) \tkzGetPoint{AV}
		\tkzInterLC(A,B)(A,AV) \tkzGetPoints{USELESS}{AK9} \tkzCompass(A,AK9)
		\tkzDefMidPoint(AV,AK9) \tkzGetPoint{AK}
		\tkzCompass(AV,AK) \tkzCompass(AK9,AK)
		\tkzInterLL(V1,V2)(A,AK) \tkzGetPoint{D}
		\tkzDrawLine(A,D) \tkzLabelLine[above left](A,D){$d$}
		\tkzInterLC(A,B)(B,M) \tkzGetPoints{MAGAIN}{MXB} \tkzCompass(B,MXB)
		\tkzDrawLine(MX,MXB) \tkzInterCC(B,MXB)(MXB,B)
		\tkzGetPoints{120}{USELESS} \tkzCompass(B,120) \tkzCompass(MXB,120)
		\tkzInterLL(B,120)(V1,V2) \tkzGetPoint{C}
		\tkzDrawLine(B,C) \tkzLabelLine[below right](B,C){$b$}
		\tkzLabelLine[below](D,C){$c$}
		\tkzDrawPolygon[fill=blue!30, opacity=.3](A,B,C,D)
		\tkzMarkRightAngles(A,M,P1 M,M2,V2 M,A,AV A,AV,V)
		\tkzDrawPoints(A) \tkzLabelPoints(A,B,D,C)
	\end{tikzpicture}
\end{center}
