Find the circumference of the circle that is within a square if the area of the square is $81 {\mathrm{cm}}^2$. (Take $\mathrm{\pi }=\frac{22}{7}$)

Find the unshaded area of the given figure.

In the given figure (not drawn to scale), $B, D, F$ and $H$ are the midpoints of $AC, CE, EG$ and $GA$ respectively. Find the area of the shaded portion, if $AGEC$ is a square of area $100 {\mathrm{cm}}^2$.

The rectangle is made of $12$ identical squares. It is divided into $4$ parts. Which of the following $2$ parts will be removed to form $\frac{3}{12}$ of the rectangle?

Find the area of the given figure (not drawn to scale)

In the given figure, all triangles are equilateral and $PQ=12$ units. Other triangles have been formed by taking the midpoints of the sides. What is the perimeter of the figure?

Ishika has designed a small oval racetrack for her remote control car. Her design is shown in the figure. What is the total distance around the track? Round your answer to the nearest whole $\mathrm{cm}$.