$\begin{array}{l} \text{Gegeben:}\\\text{Kreiszahl} \qquad \pi \qquad [] \\ \text{Kreisbogen} \qquad b \qquad [m] \\ \text{Winkel} \qquad \alpha \qquad [^{\circ}] \\ \\ \text{Gesucht:} \\\text{Radius} \qquad r \qquad [m] \\ \\ r = \frac{b\cdot 360}{\alpha \cdot \pi \cdot 2}\\ \textbf{Gegeben:} \\ \pi=3\frac{16}{113} \qquad b=5m \qquad \alpha=90^{\circ} \qquad \\ \\ \textbf{Rechnung:} \\ r = \frac{b\cdot 360}{\alpha \cdot \pi \cdot 2} \\ \pi=3\frac{16}{113}\\ b=5m\\ \alpha=90^{\circ}\\ r = \frac{5m\cdot 360}{90^{\circ} \cdot 3\frac{16}{113} \cdot 2}\\\\r=3\frac{13}{71}m \\\\ \small \begin{array}{|l|} \hline b=\\ \hline 5 m \\ \hline 50 dm \\ \hline 500 cm \\ \hline 5\cdot 10^{3} mm \\ \hline 5\cdot 10^{6} \mu m \\ \hline \end{array} \small \begin{array}{|l|} \hline alpha=\\ \hline 90 ° \\ \hline 5,4\cdot 10^{3} \text{'} \\ \hline 3,24\cdot 10^{5} \text{''} \\ \hline 100 gon \\ \hline 1,57 rad \\ \hline \end{array} \small \begin{array}{|l|} \hline r=\\ \hline 3\frac{13}{71} m \\ \hline 31,8 dm \\ \hline 318 cm \\ \hline 3,18\cdot 10^{3} mm \\ \hline 3183098\frac{22}{27} \mu m \\ \hline \end{array} \end{array}$