###### Advertisements

###### Advertisements

The radius of two circles are 20 cm and 13 cm. Find the difference between their circumferences. (Take π =`22/7`)

###### Advertisements

#### Solution

Radius of 1^{st} circle = 20 cm

Circumference of the circle = 2πr

= `2xx22/7xx20`

= `40 xx 22/7`

= 125.7 cm

The radius of 2^{nd} circle = 13 cm

Circumference of the circle = 2πr

= `2xx22/7xx13`

= `26 xx 22/7`

= 81.7

∴ The difference of circumference of two circles

= 125.7 − 81.7 cm = 44 cm

#### APPEARS IN

#### RELATED QUESTIONS

The radius of a circle is 7 cm. find the circumference of the circle.

In figure, ΔABC is an isosceles triangle with perimeter 44 cm. The base BC is of length 12 cm. Side AB and side AC are congruent. A circle touches the three sides as shown in the figure below. Find the length of the tangent segment from A to the circle.

A race track is in the form of a ring whose inner circumference is 352 m, and the outer circumference is 396 m. Find the width of the track.

A bicycle whell makes 5000 revolutions in moving 11 km. Find the diameter of the wheel

Given figure depicts an archery target marked with its five scoring areas from the centre outwards as Gold, Red, Blue, Black and White. The diameter of the region representing Gold score is 21 cm and each of the other bands is 10.5 cm wide. Find the area of each of the five scoring regions. [use π = 22/7]

Find the circumference of the circle with the following radius (Take `pi = 22/7`)

21 cm

If the circumference of a circular sheet is 154 m, find its radius. Also find the area of

the sheet. (Take `pi = 22/7`)

A gardener wants to fence a circular garden of diameter 21 m. Find the length of the rope he needs to purchase, if he makes 2 rounds of fence. Also find the costs of the rope, if it cost ₹ 4 per meter (Take `pi = 22/7`)

Shazli took a wire of length 44 cm and bent it into the shape of a circle. Find the radius of that circle. Also find its area. If the same wire is bent into the shape of a square, what will be the length of each of its sides? Which figure encloses more area, the circle or the square? (Take `pi = 22/7`)

A doorway is decorated as shown in the figure. There are four semi-circles. BC, the diameter of the larger semi-circle is of length 84 cm. Centres of the three equal semicircles lie on BC. ABC is an isosceles triangle with AB = AC. If BO = OC, find the area of the shaded region. (Take `pi = 22/7`)

A sheet of paper is in the form of rectangle ABCD in which AB = 40cm and AD = 28 cm. A semicircular portion with BC as diameter is cut off. Find the area of remaining paper.

The parallel sides of trapezium are 12 cm and 9cm and the distance between them is 8 cm. Find the area of the trapezium.

Find the area of trapezium whose parallel sides are 11 m and 25 m long, and the nonparallel sides are 15 m and 13 m long.

Find the circumferences of a circle whose radius is 7 cm.

^{°},

In the given figure, if A(P-ABC) = 154 cm^{2 }radius of the circle is 14 cm, find

(1) `∠APC`

(2) l ( arc ABC) .

The radius of a sector of a circle is 7 cm. If the measure of the arc of the sector is - three right angles; find the area of the sector in case.

The area of a minor sector of a circle is 3.85 cm^{2 }and the measure of its central angle is 36^{°}. Find the radius of the circle.

In the given figure,

\[\square\] PQRS is a rectangle. If PQ = 14 cm, QR = 21 cm, find the areas of the parts x, y, and z.

^{°}and its length is 44 cm, find the circumference of the circle.

Choose the correct alternative answer for the following question.

Choose the correct alternative answer for the following question.

A cone was melted and cast into a cylinder of the same radius as that of the base of the cone. If the height of the cylinder is 5 cm, find the height of the cone.

Choose the correct alternative answer for the following question.

The circumferences of two circles are in the ratio 2: 3. What is the ratio between their areas?

A wire when bent in the form of an equilateral triangle encloses an area of `121sqrt(3) "cm"^2`. The same wire is bent to form a circle. Find the area enclosed by the circle.

The side of a square is 10 cm. Find the area of the inscribed circle [π = 3.14]

Radii of the circles are given below, find their areas.

(1) 28 cm

(2) 10.5 cm

(3) 17.5 cm

Areas of some circles are given below find their diameters.

(1) 176 sq cm

(2) 394.24 sq cm

(3) 12474 sq cm

Diameter of the circular garden is 42 m. There is a 3.5 m wide road around the garden. Find the area of the road.

Find the area of the circle if its circumfence is 88 cm.

Find the curved surface area , the total surface area and the volume of a cone if its :

Height = 12 cm , radius = 5 cm

Find the curved surface area , the total surface area and the volume of a cone if its :

Height = 15 cm , radius = 8 cm

Find the area and perimeter of the circle with the following:

Diameter= 35 cm

The circumference of a garden roller is 280 cm. How many revolutions does it make in moving 490 meters?

Find the curved surface area , the total surface area and the volume of a cone if its :

Height = 8 cm , diameter = 12 cm

A wire bent in the form of an equilateral triangle has an area of 121 `sqrt 3` cm^{2}. If the same wire is bent into the form of a circle , find the area enclosed by the wire.

Find the area enclosed between two concentric cirdes of radii 6.3 cm and 8.4 cm. A third concentric circle is drawn outside the 8.4 cm circle, so that the area enclosed between it and 8.4 cm cirde is the same as that between two inner circles. Find the radii of the third circle correct to two decimal places .

Find the area and perimeter of the following sector :

Radius= 4.2 cm, angle at the centre is 60 °

Find the area and perimeter of the following sector :

Radius= 6 cm, angle at the centre is 70°

The speed of the car is 66 km/hour. If each wheel of the car is 140 cm in diameter, find the number of revolutions made by each wheel per minute.

The base circumferences of two cones are the same. If their slant heights are in the ratio 5 : 4, find the ratio of their curved surface areas.

Find the volume and the surface area of the spheres in the following :

Radius= 2.1 cm

Find the volume and the surface area of the spheres in the following :

Radius = 7 cm

A cylindrical bucket, whose base radius is 20 cm, is filled with water to a height of 25 cm. A heavy iron spherical ball of radius 10 cm is dropped to submerge completely in water in the bucket. Find the increase in the level of water.

Find the diameter of the sphere for the following :

Volume = `523 17/21` cm^{3}

Find the diameter of the sphere for the following :

Surface Area = 221. 76 cm^{2}

A metal wire, when bent in the form of an equilateral triangle of largest area, encloses an area of 484 `sqrt3` cm^{2}. If the same wire is bent into the form of a circle of largest area, find the area of this circle.

The cost of fencing a circular field at the rate of ₹ 240 per meter is ₹ 52,800. The field is to be ploughed at the rate of ₹ 12.50 per m^{2}. Find the cost of pouching the field.

The radius of a circle is 5 m. Find the circumference of the circle whose area is 49 times the area of the given circle.

Each wheel of a car is of diameter 80 cm. How many completer revolutions does each wheel make in 10 minutes when the car is traveling at a speed of 66 km per hour?

Draw the circumcircle of Δ PMT in which PM = 5.4, P = 60°, M = 70°.

In Figure 2, two concentric circles with centre O, have radii 21 cm and 42 cm. If ∠AOB = 60°, find the area of the shaded region.

The circumference of a circle is 440 cm. Find its radius and diameter. (Take π = `22/7`)

The diameter of a circular field is 56 m. Find its circumference and cost of fencing it at the rate of ₹80 per m. (Take π =`22/7`)

The perimeter of a square and the circumference of a circle are equal. If the length of each side of the square is 22 cm, find:**(i) **perimeter of the square.**(ii)** circumference of the circle.**(iii)** radius of the circle.

Find the diameter of a circle whose circumference is equal to the sum of circumference of circles with radius 10 cm, 12 cm, and 18 cm.

The circumference of a circle is eigth time the circumference of the circle with a radius of 12 cm. Find its diameter.

The radius of two circles are in the ratio 3 : 5, find the ratio between their circumferences.

The circumferences of two circles are in the ratio 5: 7, find the ratio between their radius.

The circumference of a circle exceeds its diameter by 18 cm. find the radius of the circle.

Construct the circumcircle of the ABC when BC = 6 cm, B = 55° and C = 70°.

A circular racing track has inner circumference 528 m and outer circumference 616 m. Find the width of the track.

The inner circumference of a circular track is 264 m and the width of the track is 7 m. Find:**(i)** the radius of the inner track.**(ii)** the radius of the outer circumference.**(iii)** the length of the outer circumference.**(iv) **the cost of fencing the outer circumference at the rate of ₹50 per m.

A bucket is raised from a well by means of a rope which is wound round a wheel of diameter 77 cm. Given that the ascends in 1 minute 28 seconds with a uniform speed of 1.1 m/sec, calculate the number of complete revolutions the wheel makes in raising the bucket. (Take π =22/7)

Complete the table below.

Radius (r) | Diameter (d) | Circumference (c) |

7 cm | ______ |
_______ |

Complete the table below.

Radius (r) | Diameter (d) | Circumference (c) |

_______ | 28 cm | _________ |

Complete the table below.

Radius (r) | Diameter (d) | Circumference (c) |

_______ | _________ | 616 cm |

Complete the table below.

Radius (r) | Diameter (d) | Circumference (c) |

_______ | _________ | 72.6 cm |

If the circumference of a circle is 176 cm, find its radius.

The radius of a circular garden is 56 m. What would it cost to put a 4-round fence around this garden at a rate of 40 rupees per metre?

The wheel of a bullock cart has a diameter of 1.4 m. How many rotations will the wheel complete as the cart travels 1.1 km?

The diameter of a circle is 5.6 cm. Find its circumference.

The diameter of the wheel of a cart is 1.05 m. How much distance will the cart cover in 1000 rotations of the wheel?

Find the area and perimeter of the circles with following: Radius = 2.8cm

Find the area and perimeter of the circles with following: Radius = 10.5cm

Find the area and perimeter of the following semicircles: Diameter = 5.6cm

The wheel of a car makes 10 revolutions per second. If its diameter is 70cm, find the speed of the car in km per hr.

A bucket is raised from a well by means of a rope wound round a wheel of diameter 35 cm. If the bucket ascends in 2 minutes with a uniform speed of 1.1 m per sec, calculate the number of complete revolutions the wheel makes in raising the bucket.

The circumference of a circle is equal to the perimeter of a square. The area of the square is 484 sq.m. Find the area of the circle.

The radius of a circular plot is 7.7 metres. How much will it cost to fence the plot with 3 rounds of wire at the rate of 50 rupees per metre?

Diameters of different circles are given below. Find their circumference (Take π = `22/7`)

d = 56 m

Find the circumference of the circles whose radii are given below.

91 mm

The diameter of the bullock cart wheel is 1.4 m. Find the distance covered by it in 150 rotations?

A wire of length 1320 cm is made into circular frames of radius 7 cm each. How many frames can be made?

A Rose garden is in the form of circle of radius 63 m. The gardener wants to fence it at the rate of ₹ 150 per metre. Find the cost of fencing?

Formula used to find the circumference of a circle is

If the circumference of a circle is 82π, then the value of ‘r’ is

Circumference of a circle is always ______.

The cost of fencing a circular race course at the rate of ₹ 8 per metre is ₹ 2112. Find the diameter of the race course

The cost of decorating the circumference of a circular lawn of a house at the rate of ₹ 55 per metre is ₹ 16940. What is the radius of the lawn?

Circumference of a circle of diameter 5 cm is ______.

The circumference of a circle whose area is 81 πr^{2}, is ______.

Circumference ‘C’ of a circle can be found by multiplying diameter ‘d’ with ______.

Circumference ‘C’ of a circle is equal to 2π × ______.

**A circle with radius 16 cm is cut into four equal parts and rearranged to form another shape as shown in the below figure:**

Does the perimeter change? If it does change, by how much does it increase or decrease?