A bridge construction company is putting cone-shaped tops on top of each bridge support to discourage birds from roosting on the bridge. Each cone will be filled with cement. How much cement will they have to put in each cone? (Use [tex]\pi=3.14[/tex].)

A) 314 cm³
B) [tex]271.2 \, \text{cm}^3[/tex]
C) 942 cm³
D) [tex]282.6 \, \text{cm}^3[/tex]



Answer :

To determine how much cement is needed to fill each cone-shaped top, we first need to use the formula for the volume of a cone. The formula for the volume [tex]\( V \)[/tex] of a cone is:

[tex]\[ V = \frac{1}{3} \pi r^2 h \][/tex]

where:
- [tex]\( r \)[/tex] is the radius of the base of the cone,
- [tex]\( h \)[/tex] is the height of the cone, and
- [tex]\( \pi \)[/tex] is approximately 3.14.

Given:
- The height of the cone [tex]\( h \)[/tex] is 12 cm,
- The base radius of the cone [tex]\( r \)[/tex] is 5 cm.

Let's plug these values into the volume formula:

[tex]\[ V = \frac{1}{3} \times 3.14 \times (5)^2 \times 12 \][/tex]

First, we need to calculate the area of the base (which is a circle):

[tex]\[ \text{Base Area} = \pi r^2 = 3.14 \times (5)^2 = 3.14 \times 25 = 78.5 \, \text{cm}^2 \][/tex]

Now, multiply the base area by the height and then by [tex]\(\frac{1}{3}\)[/tex]:

[tex]\[ V = \frac{1}{3} \times 78.5 \times 12 \][/tex]

[tex]\[ V = \frac{1}{3} \times 942 \][/tex]

[tex]\[ V = 314 \, \text{cm}^3 \][/tex]

Therefore, the amount of cement needed for each cone-shaped top is:

[tex]\[ \boxed{314 \, \text{cm}^3} \][/tex]

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