TeX source:
\begin{array}{rcl} V &=& \dfrac{4}{3}\pi \left(\dfrac{d}{2}\right)^3 \cr V &=& \dfrac{4}{3}\pi \cdot\left(\dfrac{6{,}7}{2} \, cm\right)^3 \cr V &\approx& 157{,}48 \, cm^3 \end{array}