Please help answer this!

Question

The Empire State building in New York City is approximately 1250 feet tall. How many US dimes would be in a stack of the same height? Each dime is 1.35 mm thick.

number of dimes:

each dime has a mass of 2.268 g. How much would the stack of dimes from the previous question weigh?

mass:

Answer 1

1 ft is 12 inches. 1 inch is 2.54 cm. 1 cm is 10 mm.

So 1250 ft = 1250 x 12 inches = 1250 x 12 x 2.54 cm = 1250 x 12 x 2.54 x 10 mm

Divide this by 1.35 to get the number of dimes. 282222 to the nearest integer

Mass of dimes = 282222 x 2.268 = 640079.496 g = 64.0079496 kg

Your data has 4, 3, 4 significant figures so you should quote the result to 3, ie 64.0 kg

Mike