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Calculate the volume of a cone if the height is 3 cm and the base radius is 7 cm.

A. 145 cm³
B. 154 cm³
C. 452 cm³
D. 462 cm³


Sagot :

To find the volume of a cone, you can use the formula:

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

where:
- \( r \) is the radius of the base of the cone,
- \( h \) is the height of the cone,
- \( \pi \) is a constant approximately equal to 3.14159.

Given:
- The height \( h \) is 3 cm.
- The base radius \( r \) is 7 cm.

Now, substitute the values of \( h \) and \( r \) into the formula:

[tex]\[ \text{Volume} = \frac{1}{3} \pi (7 \, \text{cm})^2 (3 \, \text{cm}) \][/tex]

First, calculate the radius squared:

[tex]\[ 7^2 = 49 \][/tex]

Next, multiply this by the height:

[tex]\[ 49 \times 3 = 147 \][/tex]

Now, include the constant \(\pi\) and the factor \(\frac{1}{3}\):

[tex]\[ \text{Volume} = \frac{1}{3} \pi \times 147 \][/tex]

[tex]\[ \text{Volume} = \frac{147}{3} \times \pi \][/tex]

[tex]\[ \text{Volume} = 49 \times \pi \][/tex]

Finally, when you multiply 49 by \(\pi\) (approximately 3.14159), you get:

[tex]\[ 49 \times 3.14159 \approx 153.94 \][/tex]

So, the volume of the cone is approximately \( 153.94 \, \text{cm}^3 \).

Therefore, the closest answer from the options given is:

B. 154 cm³