Question

Gary used candle molds, as shown below, to make candles that were perfect cylinders and spheres: A cylindrical mold is shown, the radius of the top circular section of the cylinder is labeled 2 inches and the height of the cylinder is labeled as 4 inches. On the right side of this mold is a spherical mold. The radius of this spherical mold is labeled as 2 inches. What is the approximate difference in the amount of wax needed to make a candle from each of these molds? Use π = 3.14.

16.75 cubic inches
20.93 cubic inches
24.25 cubic inches
33.49 cubic inches

Answer 1

To determine the difference between the volumes of the waxes used for each of the mold, we calculate for the volume of each of the mold.

Cylindrical mold:
V = πr²h
where V is volume, r is radius, and h is height.
Substituting the known values:
V = π(2 in)²(4 in)
V = 16π in³ = 50.26 in³

Spherical mold:
V = 4πr³/3
Substituting the radius to the equation,
V = 4π(2 in)³ / 3
V = 32π/3 in³ = 33.51 in³

The difference is calculated below:
D = 50.26 in³ - 33.51 in³
D = 16.76 in³

Hence, the answer is the first choice.