$
\text{Gegeben:}\\\text{Fläche des Dreiecks} \qquad A \qquad [m^{2}] \\
\text{Kathete} \qquad a \qquad [m] \\
\\ \text{Gesucht:} \\\text{Ankathete zu } \alpha \qquad b \qquad [m] \\
\\ b = \frac{A \cdot 2}{ a}\\ \textbf{Gegeben:} \\ A_{d}=3m^{2} \qquad a=4m \qquad \\ \\ \textbf{Rechnung:} \\
b = \frac{A \cdot 2}{ a} \\
A=3m^{2}\\
a=4m\\
b = \frac{3m^{2} \cdot 2}{ 4m}\\\\b=1\frac{1}{2}m
\\\\\\ \small \begin{array}{|l|} \hline A=\\ \hline 3 m^2 \\ \hline 300 dm^2 \\ \hline 3\cdot 10^{4} cm^2 \\ \hline 3\cdot 10^{6} mm^2 \\ \hline \frac{3}{100} a \\ \hline 0,0003 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} \small \begin{array}{|l|} \hline b=\\ \hline 1\frac{1}{2} m \\ \hline 15 dm \\ \hline 150 cm \\ \hline 1,5\cdot 10^{3} mm \\ \hline 1,5\cdot 10^{6} \mu m \\ \hline \end{array}$