The base diameter and the height of a cone are both equal to [tex]$x$[/tex] units.

Which expression represents the volume of the cone, in cubic units?

A. [tex]\pi x^2[/tex]
B. [tex]2 \pi x^3[/tex]
C. [tex]\frac{1}{3} \pi x^2[/tex]
D. [tex]\frac{1}{12} \pi x^3[/tex]



Answer :

To determine the volume of a cone with a base diameter and height both equal to [tex]\(x\)[/tex] units, we will use the formula for the volume of a cone:
[tex]\[ V = \frac{1}{3} \pi r^2 h \][/tex]

Here's the step-by-step solution:

1. Identify the given values:
- The diameter of the base of the cone is [tex]\(x\)[/tex].
- The height of the cone is [tex]\(x\)[/tex].

2. Find the radius of the base:
The radius [tex]\(r\)[/tex] is half of the diameter. So,
[tex]\[ r = \frac{x}{2} \][/tex]

3. Substitute the radius and height into the volume formula:
[tex]\[ V = \frac{1}{3} \pi \left( \frac{x}{2} \right)^2 \cdot x \][/tex]

4. Simplify the expression:
- Square the radius:
[tex]\[ \left( \frac{x}{2} \right)^2 = \frac{x^2}{4} \][/tex]
- Substitute this back into the volume formula:
[tex]\[ V = \frac{1}{3} \pi \cdot \frac{x^2}{4} \cdot x \][/tex]

5. Combine the factors:
[tex]\[ V = \frac{1}{3} \cdot \frac{1}{4} \pi x^2 \cdot x \][/tex]
[tex]\[ V = \frac{1}{12} \pi x^3 \][/tex]

6. The expression that represents the volume of the cone is:
[tex]\[ \frac{1}{12} \pi x^3 \][/tex]

Therefore, the correct answer is:
[tex]\[ \frac{1}{12} \pi x^3 \][/tex]