$1$ hectare $= \ldots \ldots \text{ } m^{2}$

The sides of a triangle measure $20 \, cm$,$24 \, cm$,and $32 \, cm$. Find its semi-perimeter. (in $, cm$)

$A$ rhombus shaped field has green grass for $18$ cows to graze. If each side of the rhombus is $30\, m$ and its longer diagonal is $48\, m$,how much area of grass field will each cow be getting (in $, m^{2}$)?

An isosceles triangle has a perimeter of $30 \, cm$ and each of the equal sides is $12 \, cm$. Find the area of the triangle.

In the figure,$\Delta ABC$ has sides $AB = 7.5\, cm$,$AC = 6.5\, cm$,and $BC = 7\, cm$. On base $BC$,a parallelogram $DBCE$ of the same area as that of $\Delta ABC$ is constructed. Find the height $DF$ of the parallelogram (in $cm$).

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 $8\,cm$?