Find the curved surface area of a cylinder whose height is $35 \, cm$ and radius of the base is $15 \, cm$. (in $cm^2$)

State whether the following statement is true or false:
An open box measuring $12\, cm \times 4\, cm \times 3\, cm$ can hold a bar of $15\, cm$ in length.

The radius of a sphere is $2r$,then its volume will be

The volume of a sphere is $4500 \pi \text{ cm}^3$,then its diameter is $\dots \text{ cm}$.

The diameter of a solid hemisphere is $7 \, cm$. Find its curved surface area and total surface area (in $cm^2$).

State whether the following statement is true or false:
The area of the base of a cylinder is $154 \, cm^{2}$ and its height is $20 \, cm$, then its volume is $3080 \, cm^{3}$.