The diagonals of a rhombus are $40 \, cm$ and $42 \, cm$. Find its area in $cm^2$.

The perimeter of an equilateral triangle is $60 \, m$. The area is

If the sides of a triangular field are $290 \, m$,$290 \, m$,and $400 \, m$,find the area of the field in $m^2$.

The area of an equilateral triangle with each side measuring $16\,cm$ is how many times the area of an equilateral triangle with each side measuring $8\,cm$?

Area of a rectangle $=$ ............

The diagonals of a rhombus are $16\,cm$ and $30\,cm$. Find its perimeter. (in $,cm$)