\(\displaystyle A= ▉ \;cm^2\)
Berechne die Fläche des linken Rechtecks.
\(A_1=\class{mathjax-input mathjax-input-1}{\mspace{3mu}\Rule{4.0em}{0.9em}{0.3em}\mspace{3mu}}\,\text{cm}^2\)
U = 2 · (a + b)