The area of a circle is $346.5 \, cm^2$. Find its radius (in $cm$).

Two minor sectors of two distinct circles have the measure of the angle at the centre equal. If the ratio of their areas is $4:9,$ then the ratio of the radii of the circles is ........

In $\odot(O, r)$,minor $\widehat{ACB}$ subtends an angle of measure $72^{\circ}$ at the centre. Then,the ratio of the length of minor $\widehat{ACB}$ and the circumference of the circle is ............

$A$ 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 $m^2$)

The length of minor $\widehat{AB}$ of a circle is $\frac{1}{4}$th of its circumference,then the measure of the angle subtended by minor $\widehat{AB}$ at the centre will be $\ldots .$ (in $^{\circ}$)

The ratio of the areas of $\odot(O, 6)$ and $\odot(P, 12)$ is ...........