The diameter of a circle with area $154\,cm ^{2}$ is $\ldots \ldots \ldots . cm$.
$3.5$
$7$
$14$
$10.5$
Areas of two circles are equal. Is it necessary that their circumferences are equal? Why?
The circumference of a circle with radius $8.4\,cm$ is $\ldots \ldots \ldots \ldots cm$.
In a circle with radius $6.3\, cm$, an are subtends an angle of measure $150$ at the centre. Find the length of this arc and the area of the sector formed by this arc.
Three circles each of radius $3.5\, cm$ are drawn in such a way that each of them touches the other two. Find the area enclosed between these circles. (in $cm ^{2}$)
The length of the minute hand of a clock is $14 \,cm$. Find the area of the region swept by it between $10.10\, AM$ to $10.30 \,AM.$