To measure the mass of a metal cube. First find it's volume, V = L (length) x W (width) x H (height), since it's a cube the L, W, and H are all the same so, V= L^3= H^3= V^3. Then you look up the density in a table or on the internet and multiple the density by volume to get mass.
V = L (length) x W (width) x H (height)
m = V * density (row)