Question

Find the surface area of a sphere if its volume is $36\pi$ (The surface area of a sphere is given by the formula $A=4\pi r^2$.)

• A. $3\pi$
• B. $9\pi$
• C. $27\pi$
• D. $36\pi$

Answer 1

The correct option is D $36\pi$

The volume of a sphere is given by $\frac{4}{3}\pi r^3$

$\therefore 36\pi =\frac{4}{3}\pi r^3$

$\therefore r^3=\frac{36\times 3}{4}$

$\therefore r=3$

Surface area of the sphere $=4\pi r^2=4\pi \times 9=36\pi$