Question

The area of the circular ring included between two concentric circles of radii $14\text{cm}$ and $10.5\text{cm}$ to the closest integer is ...........

Answer 1

Given, radius of outer circle, $R=14\text{cm}$ and

radius of inner circle, $r=10.5\text{cm}$.

Area of the circular ring$=\pi (R^2-r^2)=\frac{22}{7}({14}^2-{10.5}^2){\text{cm}}^2=269.5\approx 269{\text{cm}}^2$