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

35
35 feet and the diameter of the cylinder is
38
38 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 semi-sphere sitting on top of the cylinder, we need to calculate the volume of both shapes and then add them together.

  1. Volume of the Cylinder: The formula for the volume \( V \) of a cylinder is given by: \[ V_{\text{cylinder}} = \pi r^2 h \] where \( r \) is the radius and \( h \) is the height of the cylinder.

    The diameter of the cylinder is 38 feet, so the radius \( r \) is: \[ r = \frac{38}{2} = 19 \text{ feet} \]

    The height \( h \) of the cylinder is 35 feet. Plugging in the values: \[ V_{\text{cylinder}} = 3.14 \times (19)^2 \times 35 \]

    First, calculate \( (19)^2 \): \[ (19)^2 = 361 \]

    Now, substitute that back into the cylinder volume formula: \[ V_{\text{cylinder}} = 3.14 \times 361 \times 35 \] Calculate \( 361 \times 35 \): \[ 361 \times 35 = 12635 \]

    Now multiply by \( 3.14 \): \[ V_{\text{cylinder}} = 3.14 \times 12635 \approx 39644.9 \text{ cubic feet} \]

  2. Volume of the Semi-Sphere: The formula for the volume \( V \) of a sphere is: \[ V_{\text{sphere}} = \frac{4}{3} \pi r^3 \]

    Hence, the volume of a semi-sphere is half of that: \[ V_{\text{semi-sphere}} = \frac{1}{2} \times \frac{4}{3} \pi r^3 = \frac{2}{3} \pi r^3 \]

    Using the radius \( r = 19 \) feet: \[ V_{\text{semi-sphere}} = \frac{2}{3} \times 3.14 \times (19)^3 \]

    Calculate \( (19)^3 \): \[ (19)^3 = 6859 \]

    Now substitute back into the semi-sphere volume formula: \[ V_{\text{semi-sphere}} = \frac{2}{3} \times 3.14 \times 6859 \]

    First, calculate \( 3.14 \times 6859 \): \[ 3.14 \times 6859 \approx 21501.46 \]

    Now apply \( \frac{2}{3} \): \[ V_{\text{semi-sphere}} = \frac{2}{3} \times 21501.46 \approx 14334.31 \text{ cubic feet} \]

  3. Total Volume: Now we can add the volumes of the cylinder and the semi-sphere: \[ V_{\text{total}} = V_{\text{cylinder}} + V_{\text{semi-sphere}} \approx 39644.9 + 14334.31 \approx 53979.21 \text{ cubic feet} \]

Finally, rounding to the nearest whole number, the total volume is: \[ \boxed{53979} \text{ cubic feet} \]