The radius of a semicircular garden is $35 \, m$. One has to walk $\ldots \ldots \ldots \ldots \, m$ to make one complete round of that garden.

In the figure,a square is inscribed in a circle of diameter $d$ and another square is circumscribing the circle. Is the area of the outer square four times the area of the inner square? Give reasons for your answer.

The wheels of a car have a diameter of $80\, cm$ each. How many complete revolutions does each wheel make in $10\, minutes$ when the car is travelling at a speed of $66\, km/h$? [Use $\pi = \frac{22}{7}$]

$A$ circular pond has a diameter of $17.5 \, m$. It is surrounded by a $2 \, m$ wide path. Find the cost of constructing the path at the rate of $Rs. \, 25$ per $m^2$ (in $Rs.$).

The ratio of the areas of $\odot(O, 6)$ and $\odot(P, 12)$ is ...........

Nine circular designs are made in a square show-piece as shown in the diagram. If the radius of each circle is $21\, cm$,find the area of the region without design. (in $cm^2$)