Identify the hollow hemisphere from the above solids.

A sector containing an angle of 120 is cut off from a circle of radius 21 cm and folded into a cone. Find the curved surface area of cone. Take $\pi =\frac{22}{7}$

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

The outer radius of a hollow hemisphere is twice its inner radius. The outer radius of another hollow hemisphere is thrice its inner radius. Find the ratio of the curved surface area of the hollow hemispheres in which the outer radius of the hollow hemisphere is twice its inner radius to hollow hemisphere in which the outer radius of the hollow hemisphere is thrice its inner radius.

Write the quadrants in which the following points lie:

$\left(-4,7\right)$

The outer radius of a hollow hemisphere is $10 \mathrm{cm}$ and inner radius of a hollow hemisphere is $6 \mathrm{cm}$. Find the volume of the hollow hemisphere in cubic centimeters.

Write your answer up to two decimal points and consider $\mathrm{\pi }=\frac{22}{7}$.

Choose the correct answer:

If the curved surface area of a hemisphere is $308 sq. cm$, then its diameter will be _____.

The volume a hollow hemisphere is $1000 {\mathrm{cm}}^3$ and the outer radius of a hollow hemisphere is $10 \mathrm{cm}$. Find the inner radius the hollow hemisphere in centimeters.

Write your answer up to two decimal points and consider $\mathrm{\pi }=\frac{22}{7}$.

The volume a hollow hemisphere is $3500 {\mathrm{cm}}^3$ and the outer radius of a hollow hemisphere is $15 \mathrm{cm}$. Find the inner radius of the hollow hemisphere in centimeters.

Write your answer up to two decimal points and consider $\mathrm{\pi }=\frac{22}{7}$.

The volume a hollow hemisphere is $2500 {\mathrm{cm}}^3$ and the outer radius of a hollow hemisphere is $12 \mathrm{cm}$. Find the inner radius of the hollow hemisphere in centimeters.

Write your answer up to two decimal points and consider $\mathrm{\pi }=\frac{22}{7}$.