What length of a solid cylinder $2 cm$ in diameter must be taken to recast into a hollow cylinder of external diameter $20 cm$,$15 cm$ long and $0.25 cm$  thickness. 

The radius of the base of a cylinder is $14 \mathrm{cm}$ and its curved surface area is $880 {\mathrm{cm}}^2$. Its volume (in ${\mathrm{cm}}^3$) is______.

(Take $\pi =\frac{22}{7}$)

The lateral surface area of a cylinder is $352 {\mathrm{cm}}^2$. If its height is $7 \mathrm{cm}$, then its volume (in ${\mathrm{cm}}^3$) is:

(Take $\pi =\frac{22}{7}$)