The outer radius of a hollow hemisphere is $14 \mathrm{cm}$ and its inner radius is $7 \mathrm{cm}$. Find the curved surface area of the hollow hemisphere.

Find the total surface area of a hemisphere of diameter $10 cm$.

If the diameter of sphere is $12 cm$, then find the surface area and volume of the sphere.

What is the area of this trapezoidal garden (All measurements are in cm)? 

1. $60$ sq.cm
2. $180$ sq.cm
3. $210$ sq.cm 
4. $240$ sq.cm

The perimeter and the breadth of a rectangle are $52 cm$ and $12 cm$ respectively. Find its area in $c{m}^2$.

Find the total surface area of a hollow hemisphere whose outer and inner radii are $4.2$cm and $2.1$cm respectively