Find the circumference (in $\mathrm{cm}$) of circle whose diameter is $7 \mathrm{cm}$.

(Use $\mathrm{\pi }=\frac{22}{7}$)

(Use $\mathrm{\pi }=\frac{22}{7}$)

(Use $\mathrm{\pi }=\frac{22}{7}$)

Find the radius of a circle (in $\mathrm{cm}$) whose circumference is $52.8 \mathrm{c}\mathrm{m}$.

(Use $\mathrm{\pi }=\frac{22}{7}$)

If the radius of a circle whose circumference is $42 \mathrm{c}\mathrm{m}$, is $k \mathrm{cm}$, find $k$.(round off up to two decimal places)

(Use $\mathrm{\pi }=\frac{22}{7}$)

Find the radius of a circle (in $\mathrm{km}$) whose circumference is $6.6 \mathrm{k}\mathrm{m}$. (correct up to two decimal places)

(Use $\mathrm{\pi }=\frac{22}{7}$)

If the diameter of a circle is $k \mathrm{cm}$ whose circumference is $12.56 \mathrm{cm}$, then find the value of $k$.

(Use $\mathrm{\pi }=3.14$)

(Use $\mathrm{\pi }=\frac{22}{7}$)