The radius of the circle is $9 \mathrm{cm}$. Find its diameter in $\mathrm{cm}$.

‘O’ is the centre of the circle. The area of the shaded region in the given figure is $126 c{m}^2 , \overline{PQ} = \overline{PR}$ then the diameter $QR$ is:

In the given figure, three circles with centres $A, B, C$ respectively touch each other externally. If $AB=5cm, BC=7cm$ and $CA=6cm$, then the radius of the circle with centre $A$ is

The wheels of a car are of diameter $80 \mathrm{c}\mathrm{m}$ each. How many complete revolutions does each wheel make in 10 minutes when the car is traveling at a speed of $66 \mathrm{k}\mathrm{m}$ per hour? $\left(\mathrm{use} \pi =\frac{22}{7}\right)$

From the figure of $\odot \left(O,r\right)$ match the following. The correct option is _____

Match

$\left(1\right) \overline{AC}\cup \stackrel{⏜}{ABC}$                 $\left(a\right)2r$

$\left(2\right)\overline{OA}$ length                      $\left(b\right)r$

$\left(3\right)\overline{AC}$ length                      $\left(c\right)\mathrm{\pi r}+2\mathrm{r}$

Chords $AB$ and $CD$ are intersecting at $P$. $AB=10$ centimetres, $PB=4$ centimetres and $PD=3$ centimetres. What is the length of $PA$?

Only one circle can be drawn through three non collinear points.

In the given figure, $AB\parallel CD, \angle ABO=40°$ and $\angle CDO=35°$. Then the value of $x$ will be

In the figure, $a, b, c$ are the sides of a right triangle where $c$ is the hypotenuse. Prove that the radius $r$ of the circle which touches the sides of the triangle is given by $r=\frac{a+b+c}{2}$.

In the given figure, $XY$ is a diameter. Prove that $XY>XZ$.