If the sides of a triangle are doubled,its area

The area of a square is $196 \, cm^2$. Its side is half the radius of a circle. The circumference of the circle is equal to the breadth of a rectangle. If the perimeter of the rectangle is $712 \, cm$,what is the length of the rectangle? (in $cm$)

$A$ conical iron piece having diameter $28 \, cm$ and height $30 \, cm$ is totally immersed into the water of a cylindrical vessel,resulting in the rise of water level by $6.4 \, cm$. The diameter,in $cm$,of the vessel is

The length of a rectangle is twice the diameter of a circle. The circumference of the circle is equal to the area of a square of side $22\, cm$. What is the breadth of the rectangle if its perimeter is $668\, cm$? (in $cm$)

How many metres of cloth $5\, m$ wide will be required to make a conical tent,the radius of whose base is $7\, m$ and height is $24\, m ?$ (in $m$)

$A$ 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 $....... \text{ m}^2$.