The formula for density is D = m/V. 71.68g is the mass of the metal and 8.00cm^3 is the volume of the metal. Next, all we need to do is plug in the known values (71.68g/8.00cm^3). This gives us a final answer of 8.98g/cm^3 (three sig figs because the volume value provided has three sig figs).
Hope this helps!
