\begin{tikzpicture}[scale=1.5]
                    \clip(-.8,-.8) rectangle (2.2,2.2);
                    \def\x{1.2};
                    \tkzDefPoint(0,0){o}
                    \tkzDefPoint(2,0){a}
                    \tkzDrawCircle[dashed,color=blue](o,a)
                    \tkzDefPoint(0:\x){x}\tkzDefPoint(0:4/\x){x*}
                    \tkzDefPoint(0:4*\x/(4+(\x)^2)){c}
                    \tkzDefMidPoint(x,x*)\tkzGetPoint{d}
                    %\tkzDrawCircle[dashed](d,x)
                    %\tkzDrawCircle[dashed](c,o)
                    \tkzInterCC(d,x)(c,o)\tkzGetPoints{p1}{p}
                    \tkzDrawArc[color=black](d,p)(x)
                    \tkzDefPoint(90:\x){y}\tkzDefPoint(90:4/\x){y*}
                    \tkzDefPoint(90:4*\x/(4+(\x)^2)){cy}
                    \tkzDefMidPoint(y,y*)\tkzGetPoint{dy}
                    %\tkzDrawCircle[dashed](d,x)
                    %\tkzDrawCircle[dashed](c,o)
                    \tkzInterCC(dy,y)(cy,o)\tkzGetPoints{q}{q1}
                    \tkzDrawArc[color=black](dy,y)(q)
                    \draw (.3,1.5) node{\(a\)};\draw (1.5,.3) node{\(a\)};
                    \draw(y)--node[left]{\(a\)} (o);
                    \draw (o)-- node[below]{\(a\)}(x);
                    \tkzLabelPoints[right](p,q)
                    \tkzLabelPoint[below left](o){0}
                    \coordinate (yish) at (.1,\x);
                    \coordinate (xish) at (\x,.1);
                    \tkzMarkRightAngle[size=.1](yish,y,o)
                    \tkzMarkRightAngle[size=.1](o,x,xish)
                    \tkzMarkRightAngle[size=.1](y,o,x)
                    \tkzDrawPoints(x,o,y,p,q)
                    \tkzLabelPoint[below](x){\(x\)}
                    \tkzLabelPoint[left](y){\(xi\)}
\end{tikzpicture}