Kairay created a sculpture by forming a hemisphere with a radius of 20 inches and then removing a hemisphere with a radius of 15 inches from it. Calculate the volume of his sculpture. Use 3.14 as an approximation for pi. Round your answer to the nearest whole number. (1 point)

O 19, 363in .^ 3

O 7065in .^ 3

O 16 ,747 ln.^ 3

O 9.682in .^ 3

5

1 answer

To calculate the volume of Kairay's sculpture, we need to find the volume of the larger hemisphere and subtract the volume of the smaller hemisphere that was removed.

The volume of a hemisphere is given by the formula \( \frac{2}{3} \pi r^3 \), where \( r \) is the radius of the hemisphere.

Let's first calculate the volume of the larger hemisphere with a radius of 20 inches:

\( V_{large} = \frac{2}{3} \pi (20)^3 \)

Using 3.14 as an approximation for \( \pi \):

\( V_{large} = \frac{2}{3} \times 3.14 \times 20^3 \)
\( V_{large} = \frac{2}{3} \times 3.14 \times 8000 \)
\( V_{large} = \frac{2}{3} \times 25,120 \)
\( V_{large} = 16,746.6667 \) cubic inches

Now let's calculate the volume of the smaller hemisphere with a radius of 15 inches:

\( V_{small} = \frac{2}{3} \pi (15)^3 \)

Again using 3.14 as an approximation for \( \pi \):

\( V_{small} = \frac{2}{3} \times 3.14 \times 15^3 \)
\( V_{small} = \frac{2}{3} \times 3.14 \times 3375 \)
\( V_{small} = \frac{2}{3} \times 10,593.75 \)
\( V_{small} = 7,062.5 \) cubic inches

Finally, to get the volume of the sculpture:

\( V_{sculpture} = V_{large} - V_{small} \)
\( V_{sculpture} = 16,746.6667 - 7,062.5 \)
\( V_{sculpture} = 9,684.1667 \) cubic inches

Rounded to the nearest whole number:

\( V_{sculpture} \approx 9,684 \) cubic inches

The closest answer choice to our calculated volume is:

O 9,682in .^3