The formula for the volume of a sphere is [tex]V=\frac{4}{3} \pi r^3[/tex]. If [tex]r=\frac{3}{2} x[/tex], what is the volume of the sphere in terms of [tex]x[/tex]?

A. [tex]2 \pi x^3[/tex]
B. [tex]\frac{9}{2} \pi x^3[/tex]
C. [tex]\frac{27}{8} \pi x^3[/tex]
D. [tex]\frac{4}{3} \pi x^3[/tex]



Answer :

To find the volume of a sphere in terms of [tex]\(x\)[/tex], given that the radius [tex]\(r\)[/tex] is [tex]\(\frac{3}{2} x\)[/tex], we follow these steps:

1. Recall the formula for the volume of a sphere:
[tex]\[ V = \frac{4}{3} \pi r^3 \][/tex]

2. Substitute the given radius [tex]\( r = \frac{3}{2} x \)[/tex] into the volume formula:
[tex]\[ V = \frac{4}{3} \pi \left(\frac{3}{2} x\right)^3 \][/tex]

3. Simplify the expression [tex]\(\left(\frac{3}{2} x\right)^3\)[/tex]:
[tex]\[ \left(\frac{3}{2} x\right)^3 = \left(\frac{3}{2}\right)^3 x^3 = \frac{3^3}{2^3} x^3 = \frac{27}{8} x^3 \][/tex]

4. Substitute [tex]\(\frac{27}{8} x^3\)[/tex] back into the volume formula:
[tex]\[ V = \frac{4}{3} \pi \left(\frac{27}{8} x^3\right) \][/tex]

5. Simplify the multiplication:
[tex]\[ V = \frac{4}{3} \pi \cdot \frac{27}{8} x^3 = \frac{4 \cdot 27}{3 \cdot 8} \pi x^3 = \frac{108}{24} \pi x^3 \][/tex]

6. Reduce the fraction:
[tex]\[ \frac{108}{24} = 4.5 \][/tex]

7. Thus, the volume of the sphere in terms of [tex]\(x\)[/tex] is:
[tex]\[ V = 4.5 \pi x^3 \][/tex]

Therefore, the correct option is not listed among the choices provided [tex]\(2 \pi x^3\)[/tex], [tex]\(\frac{9}{2} \pi x^3\)[/tex], [tex]\(\frac{27}{8} \pi x^3\)[/tex], and [tex]\(\frac{4}{3} \pi x^3\)[/tex], but rather the correct expression for the volume in terms of [tex]\(x\)[/tex] is:

[tex]\[4.5 \pi x^3\][/tex]