Answer : (b) 10.25%
Let r be the radius of the circle. Then,
Increased circumference = 2πr + 2πr × \(\frac{5}{100}\) = \(\frac{21\pi r}{10}\)
∴ If R be the radius of the increased circle, then
2πR = \(\frac{21\pi r}{10}\) ⇒ R = \(\frac{21 r}{20}\)
∴ Radius of increased circle = \(\frac{21 r}{20}\)
∴ Percentage increase in area = \(\frac{\frac{41\pi r^2}{400}}{\pi r^2}\) × 100 %
= 10.25 %