College

A grain silo is composed of a cylinder and a hemisphere. The diameter is 4.4 meters, and the height of its cylindrical portion is 6.2 meters.

What is the approximate total volume of the silo? Use 3.14 for [tex]\pi[/tex] and round the answer to the nearest tenth of a cubic meter.

A. [tex]37.1 \, m^3[/tex]
B. [tex]71.9 \, m^3[/tex]
C. [tex]116.5 \, m^3[/tex]
D. [tex]130.8 \, m^3[/tex]

Answer :

We are given a grain silo made up of a cylinder and a hemisphere. The diameter of the silo is 4.4 meters, so the radius is

[tex]$$
r = \frac{4.4}{2} = 2.2\text{ m}.
$$[/tex]

The height of the cylindrical part is 6.2 meters. We use [tex]$\pi = 3.14$[/tex].

1. Volume of the Cylinder

The volume of a cylinder is given by

[tex]$$
V_{\text{cylinder}} = \pi r^2 h.
$$[/tex]

Substituting the values:

[tex]$$
V_{\text{cylinder}} = 3.14 \times (2.2)^2 \times 6.2.
$$[/tex]

Calculating the intermediate steps:

[tex]$$
(2.2)^2 = 4.84,
$$[/tex]

then

[tex]$$
V_{\text{cylinder}} \approx 3.14 \times 4.84 \times 6.2 \approx 94.225\text{ m}^3.
$$[/tex]

2. Volume of the Hemisphere

The volume of a full sphere is

[tex]$$
V_{\text{sphere}} = \frac{4}{3} \pi r^3.
$$[/tex]

Since we have a hemisphere, the volume is half that:

[tex]$$
V_{\text{hemisphere}} = \frac{1}{2} \times \frac{4}{3}\pi r^3 = \frac{2}{3} \pi r^3.
$$[/tex]

Substituting the value of [tex]$r$[/tex]:

[tex]$$
V_{\text{hemisphere}} = \frac{2}{3} \times 3.14 \times (2.2)^3.
$$[/tex]

First, compute:

[tex]$$
(2.2)^3 \approx 10.648.
$$[/tex]

Then the volume becomes:

[tex]$$
V_{\text{hemisphere}} \approx \frac{2}{3} \times 3.14 \times 10.648 \approx 22.2898\text{ m}^3.
$$[/tex]

3. Total Volume

The total volume of the silo is the sum of the volumes of the cylinder and the hemisphere:

[tex]$$
V_{\text{total}} = V_{\text{cylinder}} + V_{\text{hemisphere}} \approx 94.225 + 22.2898 \approx 116.5148\text{ m}^3.
$$[/tex]

Rounding to the nearest tenth, we get

[tex]$$
V_{\text{total}} \approx 116.5\text{ m}^3.
$$[/tex]

Thus, the approximate total volume of the silo is [tex]$\boxed{116.5\text{ m}^3}$[/tex].