The area of a circle is $346.5 \,cm ^{2}$. Find its. radius. (in $cm$)
$10.5$
$11.3$
$9.04$
$14.07$
The radii of two concentric circles are $14\, cm$ and $10.5 \,cm .$ Then, the difference between their circumferences is $\ldots \ldots \ldots . cm .$
As shown in the diagram, $\triangle ABC$ is an equilateral triangle in which $BC =70 \,cm$ and $P$ and $R$ are midpoints of $\overline{ AB }$ and $\overline{ AC }$ respectively. $\widehat{ PQR }$ is an arc of $\odot( A , AP ) .$ Find the area of the shaded region. $(\sqrt{3}=1.73)$ (in $cm^2$)
The wheel of a motor cycle is of radius $35\, cm$. How many revolutions per minute must the wheel make so as to keep a speed of $66\, km / h ?$
Find the area of the segment of a circle of radius $12 \,cm$ whose corresponding sector has a central angle of $60^{\circ}$ (Use $\pi=3.14$ ).
Find the area of the sector of a circle of radius $5\, cm ,$ if the corresponding arc length is $3.5\, cm$. (in $cm^2$)