Circles

What is the relationship between circumference and area of a circle?

If the radius of the circle is $7.2 cm$ and area of the circle is $a c{m}^2$, then find the value of $a$.$\left(take \mathrm{\pi }=\frac{22}{7}\right)$

The radii of the inner and outer circumferences of two concentric circle is  $21 m$ and $14 m$ respectively . The area of the region of two concentric circles is _____$m^2$.

Why the area of semi circle is half of the circle?

If the area of circle is $a c{m}^2$ and diameter of circle is $28$, then find the value of $a$. $\left(take \pi =\frac{22}{7}\right)$

The approximate value of $\mathrm{\pi }$, correct to two decimal places is _____.

If the radius of a circle whose perimeter is $500 \mathrm{m}$ is $x \mathrm{m}$, then find the value of $x$ in mixed fraction. Take $\mathrm{\pi }=\frac{22}{7}$. 

The radius of a wheel of an engine is $1.75 \mathrm{m}$. How many revolutions will it make in travelling $22 \mathrm{km}$? [Assume $\mathrm{\pi }=\frac{22}{7}$]

The ratio of the circumference and the _____ of a circle is always constant and it is denoted by $\mathrm{\pi }$.

The value of _____remains the same irrespective of the size of the circle.

When we multiply the pi by the square of the radius of a circle, then we get_____ of a circle

Pi is define as the ratio the circumference of the circle to its diameter.

Approximate value of pi is

The area of the shaded portion in terms of $ \pi $ = _____$ \pi $$ {\text{cm}}^{2}$

What is the area of the given figure?

(Please use $ \pi=3.14$)

The length of the arc of this semi circle is _____cm.

(Please use $ \pi =\frac{22}{7}$)

The area of this figure is _____$ {\text{cm}}^{2}$.

(Please use $ \pi =\frac{22}{7}$ and answer up to 3 decimal places)

A fountain has a granite seating around it. If the width of the seating is$70 \mathrm{cm}$ and the outer circumference of the seat is$2640 \mathrm{cm}$, the area available for seating is _____${\text{cm}}^2$.

(Please use $\mathrm{\pi }=\frac{22}{7}$)

The inner circumference of this race track is 440 m. What will be the total cost of building the fence around the outer circle if it costs &rupee; 6 per metre length?

Area of circular ring _____$ {\text{cm}}^{2}.$

(Please use $ \pi =3.14$)