Question

If the radius of a sphere is doubled then the volume of a sphere becomes

• A. doubled
• B. six times
• C. four times
• D. eight times

Answer 1

The correct option is D eight times

Let the radius of sphere is r

Then volume of sphere =$\frac{4}{3}\pi r^3$

If radius of sphere is doubled then radius is 2r

Then volume of new sphere =$\frac{4}{3}\pi (2r{)}^3=\frac{4}{3}\times 8r^3$

Then ratio of new and old sphere=$\frac{\frac{4}{3}\times 8r^3}{\frac{4}{3}{r}^3}=\frac{8}{1}$

Then the radius of sphere is doubled then volume become eight times