Answer
Volume = $1.0\times10^{2} cm^{3}$
Density = $6.2 \frac{g}{cm^{3}}$
Work Step by Step
Volume = $2.9 cm\times3.5 cm \times 10.0 cm = 1.0\times10^{2}$ $cm^{3}$
Given, Mass = 615.0 g
Density= $\frac{Mass}{Volume} = \frac{615.0g}{1.0\times10^{2}cm^{3}}$ = 6.2 g/$cm^{3}$