$\begin{array}{l} \text{Gegeben:}\\\text{Grundlinie c} \qquad c \qquad [m] \\ \text{Höhe} \qquad h \qquad [m] \\ \text{Fläche} \qquad A \qquad [m^{2}] \\ \\ \text{Gesucht:} \\\text{Grundlinie a} \qquad a \qquad [m] \\ \\ a = \frac{2\cdot A}{ h} - c\\ \textbf{Gegeben:} \\ c=4m \qquad h=5m \qquad A=20m^{2} \qquad \\ \\ \textbf{Rechnung:} \\ a = \frac{2\cdot A}{ h} - c \\ c=4m\\ h=5m\\ A=20m^{2}\\ a = \frac{2\cdot 20m^{2}}{ 5m} - 4m\\\\a=4m \\\\\\ \small \begin{array}{|l|} \hline c=\\ \hline 4 m \\ \hline 40 dm \\ \hline 400 cm \\ \hline 4\cdot 10^{3} mm \\ \hline 4\cdot 10^{6} \mu m \\ \hline \end{array} \small \begin{array}{|l|} \hline h=\\ \hline 5 m \\ \hline 50 dm \\ \hline 500 cm \\ \hline 5\cdot 10^{3} mm \\ \hline 5\cdot 10^{6} \mu m \\ \hline \end{array} \small \begin{array}{|l|} \hline A=\\ \hline 20 m^2 \\ \hline 2\cdot 10^{3} dm^2 \\ \hline 2\cdot 10^{5} cm^2 \\ \hline 2\cdot 10^{7} mm^2 \\ \hline \frac{1}{5} a \\ \hline 0,002 ha \\ \hline \end{array} \small \begin{array}{|l|} \hline a=\\ \hline 4 m \\ \hline 40 dm \\ \hline 400 cm \\ \hline 4\cdot 10^{3} mm \\ \hline 4\cdot 10^{6} \mu m \\ \hline \end{array} \end{array}$