Find the circumference of a circle in $\mathrm{cm}$, whose diameter is $4.9\mathrm{cm}$.

(Take $\mathrm{\pi }=\frac{22}{7}$)

Taking $\mathrm{\pi }=3.14$, Find the circumference of a circle in $\mathrm{cm}$, whose radius is $8\mathrm{cm}$.

Taking $\mathrm{\pi }=3.14$, Find the circumference of a circle in $\mathrm{cm}$, whose radius is $15\mathrm{cm}$.

Taking $\mathrm{\pi }=3.14$, find the circumference of a circle in $\mathrm{cm}$, whose radius is $20 \mathrm{cm}$.

Calculate the radius of a circle in $\mathrm{cm}$, whose circumference is $44 \mathrm{cm}$. $($Take $\mathrm{\pi }=\frac{22}{7})$

How many times will a wheel of radius $35\mathrm{cm}$ be rotated to travel $660\mathrm{cm}$?

(Take $\mathrm{\pi }=\frac{22}{7}$)