Arectangular block of lead (pb) measures 20.0 mm x 30.0 mm x 45.0 mm. if the density of pb is 11.34 g/cm3, calculate the mass of the block

1. D=M / V
Convert mm to cm then multiply to get V.
V=20.0mm * 30.0mm * 45.0mm
V=2.00cm * 3.00cm * 4.50cm=27.0cm3
11.34g/cm3=M / 27.0cm3
M= 306g

2. A cube has the same dimensions for length, height, and width, therefore volume is 1.55cm*1.55cm*1.55cm=3.724cm3
D=M / V
D=71.9g / 3.724cm3
D=19.3g/cm3

3. Volume of the sample is 41.7mL-25.5mL=16.2mL or 16.2cm3 because 1mL=1cm3
D=M / V
D=43.6g / 16.2cm3
D=2.69g/cm3

4. D=M / V
D= 3175g / 2.00m*2.00m*5.00m
Convert m to cm and multiply to get volume
D=3175g / 2.00x10^7cm3
D=1.59x10^-4g/cm3 or 0.000159g/cm3
because 1cm3=1mL
D=1.59x10^-4g/mL or 0.000159g/mL
Since I do not have the table you need to reference, I have listed the volume in scientific notation and in decimal form for you to compare to your table.