$\begin{array}{l} \text{Gegeben:}\\\text{Diagonale f} \qquad f \qquad [m] \\ \text{Diagonale e} \qquad e \qquad [m] \\ \\ \text{Gesucht:} \\\text{Fläche} \qquad A \qquad [m^{2}] \\ \\ A = \frac{1}{2}\cdot e\cdot f\\ \textbf{Gegeben:} \\ f=0,002m \qquad e=\frac{2}{5}m \qquad \\ \\ \textbf{Rechnung:} \\ A = \frac{1}{2}\cdot e\cdot f \\ f=0,002m\\ e=\frac{2}{5}m\\ A = \frac{1}{2}\cdot \frac{2}{5}m\cdot 0,002m \\\\ A=0,0004m^{2} \\\\\\ \small \begin{array}{|l|} \hline f=\\ \hline 0,002 m \\ \hline \frac{1}{50} dm \\ \hline \frac{1}{5} cm \\ \hline 2 mm \\ \hline 2\cdot 10^{3} \mu m \\ \hline \end{array} \small \begin{array}{|l|} \hline e=\\ \hline \frac{2}{5} m \\ \hline 4 dm \\ \hline 40 cm \\ \hline 400 mm \\ \hline 4\cdot 10^{5} \mu m \\ \hline \end{array} \small \begin{array}{|l|} \hline A=\\ \hline 0,0004 m^2 \\ \hline \frac{1}{25} dm^2 \\ \hline 4 cm^2 \\ \hline 400 mm^2 \\ \hline 4\cdot 10^{-6} a \\ \hline 4\cdot 10^{-8} ha \\ \hline \end{array} \end{array}$