Question

If the radius of the circle is increased by $100$, then the area is increased by

• A. $100$%
• B. $200$%
• C. $300$%
• D. $400$%

Answer 1

The correct option is C $300$%

We know that the area of a circle $=\pi r^2$.

Now when we increase the radius by $100\%$,

Radius $=2r$.

Now, area of the circle $=\pi (2r{)}^2=4\pi r^2$.

Therefore, increased area $=3\pi r^2$.

Hence, the area increased by $300\%$.