We assume the sample is shaped like a perfect cylinder. The volume is given by:
$$V = \pi \cdot \left( \frac{7,2}{2} \right)^2 \cdot 1,8 = \pi \cdot 3,6^2 \cdot 1,8 = 73,2\,\mathrm{cm^3}$$
Then the approximate density is:
$$
\rho = \frac{98,7}{73,2} = 1,348\,\mathrm{g/cm^3} =...