Answer
$(a)\lt(b)\lt(c)$
Work Step by Step
Mass= Density$\times$Volume
(a) Density=$7.86\,g/cm^{3}$
Volume=$81.5\,cm\times2.1\,cm\times1.6\,cm=273.84\,cm^{3}$
Mass=$7.86\,g/cm^{3}\times273.84\,cm^{3}=2.15\times10^{3}\,g$
(b) Density=$2.70\,g/cm^{3}$
Volume=$1212\,cm\times362\,cm\times0.003\,cm=1316.232\,cm^{3}$
Mass=$2.70\,g/cm^{3}\times1316.232\,cm^{3}=3.55\times10^{3}\,g$
(c) Density=$0.998\,g/cm^{3}$
Volume=$4.051\,L=4.051\,L\times\frac{1000\,cm^{3}}{1\,L}=4.051\times10^{3}\,cm^{3}$
Mass=$0.998\,g/cm^{3}\times4.051\times10^{3}\,cm^{3}=4.04\times10^{3}\,g$
Order in terms of increasing mass is:
$(a)\lt(b)\lt(c)$
