Hallo,
$$ \begin{array}{ccccl} & 40cm^2 & = & \frac 1 2 \cdot 10cm \cdot f \\ \Rightarrow & 40cm^2 & = & 5cm \cdot f & | \div 5cm \\ \Rightarrow & \frac {40cm^2} {5cm} & = & \frac {5cm} {5cm} \cdot f \\ \Rightarrow & \frac {40} 5 cm & = & 1 \cdot f \\ \Rightarrow & 8cm & = & f \end{array} $$
Grüße Christian
Sonstiger Berufsstatus, Punkte: 29.81K