The area of a ring whose outer and inner radii are respectively $20 \, cm$ and $15 \, cm$ is? (in $cm^2$)

$A$ wire when bent in the form of a circle encloses an area of $1386 \, cm^2$. What will be the enclosed area when the same wire is bent into the form of an equilateral triangle?

The perimeter of a non-square rhombus is $20 \, cm$. One of its diagonals is $8 \, cm$. The area of the rhombus is.........$cm^2$

If the area of a triangle is $150 \, m^{2}$ and the ratio of the base and the height is $3:4$,then find its height in $m$.

Find the perimeter and area of the shaded portion of the adjoining diagram.

Perimeter of a rhombus is $2p$ units and the sum of the lengths of its diagonals is $m$ units,then the area of the rhombus is