A semi-sphere sits on top of a cylinder. The height of the cylinder is

27 feet and the diameter of the cylinder is
25 feet. What is the total volume? Use 3.14 for π.

Round your answer to the nearest whole number.

1 answer

To find the total volume of the solid consisting of a cylinder topped with a semi-sphere, we need to calculate the volume of each part separately and then sum them.

1. Volume of the Cylinder

The formula for the volume \( V \) of a cylinder is given by:

\[ V = \pi r^2 h \]

where \( r \) is the radius of the base, and \( h \) is the height.

  • Diameter of the cylinder = 25 feet, so the radius \( r \) is:

\[ r = \frac{25}{2} = 12.5 \text{ feet} \]

  • Height \( h \) of the cylinder = 27 feet.

Now substituting the values into the volume formula:

\[ V_{cylinder} = \pi (12.5)^2 (27) \]

Calculating \( (12.5)^2 \):

\[ (12.5)^2 = 156.25 \]

Now, substituting that back into the volume formula:

\[ V_{cylinder} = \pi (156.25) (27) \]

Calculating \( (156.25)(27) \):

\[ 156.25 \times 27 = 4218.75 \]

Now, substituting this into the volume formula while using \( \pi \approx 3.14 \):

\[ V_{cylinder} = 3.14 \times 4218.75 \approx 13264.125 \]

2. Volume of the Semi-Sphere

The formula for the volume \( V \) of a sphere is:

\[ V = \frac{4}{3} \pi r^3 \]

Since we need the volume of a semi-sphere, we take half of the volume of the sphere:

\[ V_{semi-sphere} = \frac{1}{2} \times \frac{4}{3} \pi r^3 = \frac{2}{3} \pi r^3 \]

The radius \( r \) of the semi-sphere is the same as that of the cylinder, which is 12.5 feet.

Now substituting that into the volume formula:

\[ V_{semi-sphere} = \frac{2}{3} \pi (12.5)^3 \]

Calculating \( (12.5)^3 \):

\[ (12.5)^3 = 12.5 \times 12.5 \times 12.5 = 1953.125 \]

Now substituting back into the volume formula:

\[ V_{semi-sphere} = \frac{2}{3} \pi (1953.125) \]

Calculating \( \frac{2}{3} \times 1953.125 \):

\[ \frac{2}{3} \times 1953.125 \approx 1302.08333 \]

Now substituting that back with \( \pi \approx 3.14 \):

\[ V_{semi-sphere} = 3.14 \times 1302.08333 \approx 4099.626 \]

3. Total Volume

Now we add the volumes of the cylinder and semi-sphere:

\[ V_{total} = V_{cylinder} + V_{semi-sphere} \approx 13264.125 + 4099.626 \approx 17363.751 \]

Rounding to the nearest whole number:

\[ V_{total} \approx 17364 \]

Final Answer

The total volume of the solid is approximately 17364 cubic feet.