\ANG{
%
%%\item
%
\begin{minipage}[t]{8cm}
Die Fl"achen  $A$, $B$ und $C$ werden von den Seiten des 
gleichschenklig-rechtwinkligen  Dreiecks $PQR$ sowie von den Kreisb"ogen 
um die Ecken $Q$ und $R$ und den Seitenmittelpunkt $M$ begrenzt. 
\begin{enumerate}      
         \item
         Berechnen Sie die Fl"acheninhalte von  $B$ und $C$ in Ab\-h"angig\-keit von 
         $a= {1 \over 2} \overline{QR} $. 
         \item
         Zeigen Sie, dass die F"acheninhalte von $A$ und $B$ gleich sind.
       
\end{enumerate}
\end{minipage}
\begin{minipage}[b]{6.5cm}
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                     <z,z,0.5pt,0.5pt> 13      1.72      3.65   15        2.30      5.00
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                     <z,z,0.5pt,0.5pt> 21      4.62     11.44   23        5.60     15.20   
                     <z,z,0.5pt,0.5pt> 24      6.14     18.00   25        6.70     25.00
                     <z,z,0.5pt,0.5pt> 28      8.58        22   30       10.00     20
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                     <z,z,0.5pt,0.5pt> 10     47.91     48.99 13     46.35     48.28
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                     <z,z,0.5pt,0.5pt> 30     20.00     40.00 33     17.00     37.56
                     <z,z,0.5pt,0.5pt> 35     15.00     35.71 35.35     14.65     35.36
                     <z,z,0.5pt,0.5pt> 38     12.00     32.50 40     10.00     30.00
                     <z,z,0.5pt,0.5pt> 43      7.00     25.51 45      5.00     21.79
                     <z,z,0.5pt,0.5pt> 47      3.00     17.06 48      2.00     14.00
                     <z,,0.5pt,0.5pt>  49      1.00      9.95 50      0.00      0.00 /



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}
\LSG{
         Es ist $B={1 \over 2} a^2 ({1\over  2} \pi -1)$. $C$ hat die vierfache
         Fl"ache vermindert um die von $B$, ist also dreimal so gro"s.
         $A$ und $B$ sind gleich gro"s, weil der Halbkreis um $M$ und der 
         Viertelkreis
         um $Q$ denselben Fl"acheinhalt haben.
 }        


