Take $\mathrm{\pi }=\frac{22}{7}$

The diameter of Planet Venus is $12278 \mathrm{km}.$ If the circumference of circle is $k \mathrm{km}$, then find the value of $k$.

Find the diameter, and the radius of the circle, given the circumference as $22 \mathrm{cm}$ $\left(\mathrm{Take} \mathrm{\pi }=3\frac{1}{7}\text{ or }\frac{22}{7}\right)$.

Find the diameter, and the radius of circle, given the circumference as $61.6 \mathrm{m}$ $\left(\mathrm{Take} \mathrm{\pi }=3\frac{1}{7}\text{ or }\frac{22}{7}\right)$.

The ratio of the radii of two wheels is $2:5$. What is the ratio of their circumferences?

A wire is in the form of a circle of radius $21 \mathrm{cm}$. It is bent into an equilateral triangle. If the side of the triangle is $k \mathrm{cm}$, then find the value of $k$. $\left(\text{ Take }\mathrm{\pi }=\frac{22}{7}\right)$

In the figure below, the radius is $10 \mathrm{cm}$. Find the perimeter of the quarter of the circle (in $\mathrm{cm}$).  (Take $\mathrm{\pi }=3.14$)

Find the perimeter of the following shape (in $\mathrm{cm}$) to $1$ decimal place (Take $\mathrm{\pi }=3.14$)

Find the perimeter of the following shape (in $\mathrm{m}$) to $1$ decimal place (Take $\mathrm{\pi }=3.14$)

Find the perimeter of the following shape (in $\mathrm{cm}$) to $1$ decimal place (Take $\mathrm{\pi }=3.14$)