$
\text{Gegeben:}\\\text{Umfang} \qquad U \qquad [m] \\
\text{Länge} \qquad a \qquad [m] \\
\\ \text{Gesucht:} \\\text{Breite} \qquad b \qquad [m] \\
\\ b = \frac{U - 2\cdot a}{ 2}\\ \textbf{Gegeben:} \\ U=50m \qquad a=3m \qquad \\ \\ \textbf{Rechnung:} \\
b = \frac{U - 2\cdot a}{ 2} \\
U=50m\\
a=3m\\
b = \frac{50m - 2\cdot 3m}{ 2}\\\\b=22m
\\\\\\ \small \begin{array}{|l|} \hline a=\\ \hline 3 m \\ \hline 30 dm \\ \hline 300 cm \\ \hline 3\cdot 10^{3} mm \\ \hline 3\cdot 10^{6} \mu m \\ \hline \end{array} \small \begin{array}{|l|} \hline U=\\ \hline 50 m \\ \hline 500 dm \\ \hline 5\cdot 10^{3} cm \\ \hline 5\cdot 10^{4} mm \\ \hline 5\cdot 10^{7} \mu m \\ \hline \end{array} \small \begin{array}{|l|} \hline b=\\ \hline 22 m \\ \hline 220 dm \\ \hline 2,2\cdot 10^{3} cm \\ \hline 2,2\cdot 10^{4} mm \\ \hline 2,2\cdot 10^{7} \mu m \\ \hline \end{array}$