If the perimeter of a semi-circular protractor is $36 \, cm$,then its diameter is ...... $cm$?

$A$ circular swimming pool is surrounded by a concrete wall $4 \ m$ wide. If the area of the concrete wall surrounding the pool is $11/25$ that of the pool,then the radius (in $m$) of the pool is

Find the perimeter (in $cm$) of a semicircle of radius $28\, cm$.

Among a square of perimeter $44\, cm$ and a circle of circumference $44\, cm,$ which figure has a larger area and by how much?

If the radius of one circle is $12$ times the radius of another,how many times does the area of the greater circle contain the area of the smaller circle?

$A$ person $A$ takes $15 \text{ seconds}$ to cross a rectangular field diagonally walking at a speed of $52 \text{ m/min}$. $A$ person $B$ takes the same time to cross the same field along its sides (length + width) walking at a speed of $68 \text{ m/min}$. The area of the field is $....... \text{ m}^2$.