Answered

A machine coats metal spheres with a plastic coating. The metal spheres have a radius of 9 mm. The spheres formed by the metal and plastic coating have a radius of 12 mm.


How much plastic coating is on each sphere?

Use 3.14 to approximate pi and express your final answer in hundredths.

Verified Answer :

iGreen

Find the volumes of the two spheres and subtract.

V = 4/3 pi r^3

V = 4/3 3.14 9^3

Simplify exponent:

V = 4/3 3.14 729

Multiply:

V = 3052.08

V = 4/3 pi r^3

V = 4/3 3.14 12^3

Simplify exponent:

V = 4/3 3.14 1728

Multiply:

V = 7234.56

Subtract the two volumes:

7234.56 - 3052.08 = 4182.48

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