Question

A spherical shell has a outer radius $14$ m and inner radius $7$ m. What's the volume of the sphere?

• A. $\approx 9000m^3$
• B. $\approx 8000m^3$
• C. $\approx 10000m^3$
• D. $\approx 7000m^3$

Answer 1

The correct option is C $\approx 10000m^3$

Outer radius, $R=14$ cm
Inner radius, $r=7$ cm
Volume = $\frac{4}{3}\pi (R^3-r^3)$
= $\frac{4}{3}\pi ({14}^3-7^3)$
= $\frac{4}{3}\pi (2744-343)$
= $\frac{4}{3}\pi \left(2401\right)$
= $\frac{9604\pi }{3}$
= $3201.33\pi$
$\approx 10000m^3$