TeX Quellcode:

\begin{array}{rcl} A_O &=& \pi r(r+s) \cr A_O &=& \pi r\left(r+\sqrt{r^2+h^2}\right) \cr A_O &=& \pi \cdot (14 \, cm)\cdot\left(14\,cm + \sqrt{(14\, cm)^2+(31\, cm)^2}\right) \cr A_O &\approx& 2.111{,}80 \, cm^2 \end{array}