Areas Related to Circles question bank (Maths)

The cost of fencing a circular field at the rate of $Rs. 24$ per metre is $Rs. 5280$. The field is to be ploughed at the rate of $Rs. 0.50$ per $m^2$. Find the cost of ploughing the field (Take $\pi = \frac{22}{7}$). (in $Rs.$)

The radii of two circles are $19\, cm$ and $9\, cm$ respectively. Find the radius of the circle which has circumference equal to the sum of the circumferences of the two circles. (in $cm$) [use $\pi=\frac{22}{7}$]