The radius of a circle is $12 \, cm$. Find its circumference and area $(\pi = 3.14)$.

In a circle with radius $20\, cm$,the area of a sector formed by an arc of length $10\, cm$ is ............. $cm^2$.

The ratio of the radii of two circles is $4: 5$. Then,the ratio of their areas is...........

If the length of an arc of a circle of radius $r$ is equal to that of an arc of a circle of radius $2r$,then the angle of the corresponding sector of the first circle is double the angle of the corresponding sector of the other circle. Is this statement false? Why?

In $\odot (P, 20)$,the area of a minor sector is $150\, cm^2$. The length of the arc corresponding to that sector is $\dots\, cm$.

In $\odot(O, r)$,the length of minor $\widehat{ACB}$ is $\frac{1}{6}$ times the circumference of the circle. Then,the measure of the angle subtended at the centre by minor $\widehat{ACB}$ is ......... (in $^{\circ}$)