Find the circumference and the area of a circle with diameter $42 \, cm$.

What is the area (in $cm^2$) of a square inscribed in a circle of radius $8 \, cm$?

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 a circle,the ratio of the areas of two distinct minor sectors is $1:4$. Then,the ratio of the angles at the centre for those minor sectors is $\ldots \ldots \ldots \ldots$.

In the figure,a circle is inscribed in a square of side $5 \, cm$ and another circle is circumscribing the square. Is it true to say that the area of the outer circle is two times the area of the inner circle? Give reasons for your answer.

$A$ field is in the shape of an equilateral triangle in which the length of each side is $70\, m$. $A$ cow is tethered at one of its vertices by a $5\, m$ long rope. Find the area of the region in the field in which the cow can graze. $(\pi = 3.14)$ (in $m^2$)