One room in Joseph’s house has a circular glass roof. The diameter of the roof is $2.8 m$.

The circular frame of the glass roof is made of wire. What is the length of the wire?

$\left(\mathrm{\pi }=\frac{22}{7}\right)$ Find the perimeter of the given figure.

A man runs round a circular field of radius $50 \mathrm{m}$ at a speed of $12 \mathrm{km}/\mathrm{hr}$. How much time is taken by the man to run twenty rounds of the field?

The circumferences of two concentric rings are $88 \mathrm{cm}$ and $66 \mathrm{cm}$ respectively. Find the width (in $\mathrm{cm}$) between the rings.

Manju made a design for rangoli using four circular arcs of radius $r$, leaving an empty square inside as shown in the figure below. The centres of the circles are the vertices of the square.

Which of the following is the perimeter of the shape above?

The shape of the stadium in the figure below is a rectangle with each end attached to a semicircle. The length and width of the stadium are $200 \mathrm{m}$, and $40 \mathrm{m}$ respectively.

What is the perimeter of the stadium?