TeX source:
\begin{array}{rcl} A_O &=& 2\pi r(r+h) \cr A_O &=& 2\pi r\left(r+\dfrac{V}{\pi r^2}\right) \cr A_O &=& 2\pi\cdot 3{,}75\, cm \left(3{,}75\, cm+\dfrac{250\, cm^3}{\pi \left(3{,}75\, cm\right)^2}\right) \cr A_O &\approx& 221{,}69 \, cm^2 \end{array}