Two rectangular sheets of sizes $2\mathrm{\pi }\times 4\mathrm{\pi }$ square unit and $\mathrm{\pi }\times 5\mathrm{\pi }$ square unit are available. A hollow right circular cylinder can be formed by joining a pair of parallel sides of any sheet. What is the maximum possible volume of the circular cylinder that can be formed this way?

Consider the following statements in respect of three straight lines $A, B$ and $C$ on a plane:

$1.$ If $A$ and $C$ are parallel and $B$ and $C$ are parallel, then $A$ and $B$ are parallel.

$2.$ If $A$ is perpendicular to $C$ and $B$ is perpendicular to $C$, then $A$ and $B$ are parallel.

$3.$ If the acute angle between $A$ and $C$ is equal to the acute angle between $B$ and $C$, then $A$ and $B$ are parallel.

Which of the above statements are correct?

An arc of a circle subtends an angle $𝜋$ at the centre. If the length of the arc is $22 \mathrm{cm}$, then what is the radius of the circle? 

$(Take 𝜋=\frac{22}{ 7} )$