Question

If the radius of a circle is increased by $10$%, then the corresponding area of the new circle will be ................. . ($\pi =3.14$)

• A. $121\pi r^2$
• B. $12.1\pi r^2$
• C. $1.21{\pi }^2$
• D. None of the given three.

Answer 1

Answer: (D)

None of the given three.

Assume the radius of the original circle $=r$
Area $=\pi r^2$
As the radius is increased by $10$%. So, radius of the new circle $R=\frac{10r}{100}+r=1.1r$
Area of new circle $=\pi R^2=\pi {\left(1.1r\right)}^2=1.21\pi r^2$
Hence none of the given options are correct.