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

The ratio of the corresponding sides of two similar triangles is $3:4$. The ratio of their areas is

The perimeter of an isosceles triangle is $14 \ cm$. The lateral side and the base are in the ratio $5:4$. The area of the triangle in $cm^2$ is:

$A$ room is $7 \text{ m}$ long and $5 \text{ m}$ broad. The doors and windows occupy $5 \text{ m}^2$. The cost of papering the remaining part of the walls with paper $75 \text{ cm}$ wide,at ₹ $4.20$ per piece of $13 \text{ m}$,is ₹ $39.20$. Find the height of the room (in $\text{m}$).

If the diagonal of a square is doubled to make another square,the area of the new square will

In the given figure,$QRST$ is a square. If the area of each circle is $2 \pi$,then find the area of square $QRST$?