Volume of cube = s\(^3\) = 10\(^3\) = 1000cm\(^3\)

Volume of cube submerged = 10 cm x 10 cm x 4.5 cm = 450 cm\(^3\)

Volume of water displaced = volume of cube submerged = 450 cm\(^3\)

Mass of water displaced = 1 cm\(^3\) x 450 cm\(^3\) = 450g (density of water is 1 cm\(^3\))

Mass of cube = V\(_{cube}\) x \(\rho_{cube}\)

But, mass of cube = mass of water displaced

1000 cm\(^3\) x \(\rho_{cube}\) = 450g

\(\rho_{cube}\) = \(\frac{450}{1000}\) = 0.45 g/cm\(^3\)