The diameter of a circle with area $38.5\,m ^{2}$ is $\ldots \ldots \ldots \ldots m$.
$7$
$3.5$
$14$
$10.5$
The area of a circle is $38.5\, m ^{2}$, then its circumference will be $\ldots \ldots \ldots \ldots m$.
The area of a circular playground is $22176\, m ^{2}$. Find the cost of fencing this ground at the rate of $Rs.\, 50$ per $metre.$ (in $Rs.$)
The radit of two concentric circles are $23\, cm$ and $16 \,cm .$ Find the area of the circular ring formed by the circles. (in $cm^2$)
The length of a square field is $50\, m .$ A cow is tethered at one of the vertices by a $3\, m$ long rope. Find the area of the region of the field in which the cow can graze. $(\pi=3.14)$ (in $m^2$)
The length of the minute hand of a clock is $17.5\, cm$. Find the area of the region swept by it in $15$ minutes time duration. (in $cm^2$)