\documentclass{article} \usepackage[pdftex,active,tightpage]{preview} \setlength\PreviewBorder{2mm} \usepackage{tikz} \usepackage{tkz-euclide} \usetkzobj{all} \usetikzlibrary{shapes, calc, decorations} \usepackage{amsmath,amssymb} \usepackage{helvet} \usepackage[eulergreek]{sansmath} \begin{document} \begin{preview} \begin{tikzpicture}[scale=1.5,font=\sansmath\sffamily] \tkzDefPoint(0,0){A} \tkzDefPoint(4,0){B} \tkzDefPoint(2,0){M} \tkzDefPoint(3,2){H} \tkzInterLC[/tikz/overlay](M,H)(M,B) \tkzGetPoints{E}{C} \tkzLabelPoints[above right](C) \tkzMarkAngle[fill=blue!30,size=0.6cm,opacity=.5](C,B,A) \tkzLabelAngle[pos=0.4](A,B,C){$\beta$} \tkzMarkAngle[fill=blue!30,size=0.6cm,opacity=.5](M,C,B) \tkzLabelAngle[pos=0.4](B,C,M){$\beta$} \tkzMarkAngle[fill=blue!30,size=0.6cm,opacity=.5](B,M,C) \tkzLabelAngle[pos=0.4](B,M,C){$\delta$} \tkzMarkAngle[fill=blue!30,size=0.6cm,opacity=.5](M,A,C) \tkzLabelAngle[pos=0.4](M,A,C){$\alpha$} \tkzMarkAngle[fill=blue!30,size=0.6cm,opacity=.5](A,C,M) \tkzLabelAngle[pos=0.4](A,C,M){$\alpha$} \tkzMarkAngle[fill=blue!30,size=0.6cm,opacity=.5](C,M,A) \tkzLabelAngle[pos=0.4](C,M,A){$\gamma$} \tkzDrawSector[thick](M,B)(A) \tkzLabelSegment[below=-1pt](A,M){$r$} \tkzLabelSegment[below=-1pt](M,B){$r$} \tkzLabelSegment[right=-1pt](M,C){$r$} \tkzLabelPoints[below left](A) \tkzLabelPoints[below right](B) \tkzLabelPoints[below](M) \tkzDrawSegments(A,B B,C C,A) \tkzDrawSegments(M,B B,C C,M) \end{tikzpicture} \end{preview} \end{document}