Lab 2E Finding the Thickness of Aluminum

Finding the thickness of aluminum foil combines two different concepts to measure the thickness:
Volume of a solid: V = L x W x H (length x width x height)
Density of a substance: D = m / V (mass / Volume)

Height being the thickness of the aluminum sheet being measured. Therefore in the experiment you determine the thickness in the volume equation.
Aluminum foil 17cm x 15cm (1.04g)
Start with density: (density of aluminum = 2.70g/cm3)
2.70 = 1.04g/V
    V = 0.39

Then using the volume in the Volume equation:
0.39 = 17 x 15 H
0.39 = 255 x H
H = 0.39 / 255
H = 1.53x10(-3)cm

Then find the average of 3 pieces of aluminum foil:
1.53x10(-3)cm +
1.48x10(-3)cm +
1.52x10(-3)cm +
/3 = 1.51x10(-3)cm

Then find the % off the acceptable thickness of aluminum foil (1.55x10(-3)cm)

finding the average by (1.51x10(-3)cm) - (1.55x10(-3)cm) / 1.55x10(-3)cm = 2.5%