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

The area of a circle is $75.46\, cm^{2}$. Find its circumference. (in $cm$)

In $Fig.$,$ABCD$ is a square of side $14 \, cm$. With centres $A, B, C$ and $D$,four circles are drawn such that each circle touches externally two of the remaining three circles. Find the area of the shaded region (in $cm^2$). $\left[\text{Use } \pi = \frac{22}{7}\right]$

$A$ chord of a circle of radius $20\, cm$ subtends an angle of $90^{\circ}$ at the centre. Find the area of the corresponding major segment of the circle. (Use $\pi=3.14$) (in $cm^2$)

The maximum area of a triangle inscribed in a semicircle having radius $10 \, cm$ is $\ldots \ldots \ldots \, cm^2$.

The length of a minor arc of a circle is given by the formula $\ldots \ldots \ldots \ldots$