TeX Quellcode:

\begin{array}{rclcl} \sin(\alpha) &=& \dfrac{a}{c} & \vert & \cdot c \cr a &=& c \cdot \sin(\alpha) \cr a &=& 11 \cdot \sin \left( \dfrac{\pi}{8} \right) \cr a & \approx & 4{,}21 \, cm \end{array}