###### Advertisements

###### Advertisements

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

###### Advertisements

#### Solution

Length of the wire = 1320 cm

Radius of each circular frame = 7 cm

Circumference of the frame 2πr units = `2 xx 22/7 xx 7 "cm"`

= 2 × 22

= 44 cm

∴ Number of frames made = `"length of the wire"/"circumference of one frame"`

= `1320/44`

= 30

30 frames can be made.

#### 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.

In the figure given below, PQRS is square lawn with side PQ = 42 metres. Two circular flower beds are there on the sides PS and QR with centre at O, the intersections of its

diagonals. Find the total area of the two flower beds (shaded parts).

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.

In the given figure, ∆ ABC is a right-angled triangle in which ∠ A is 90°. Semicircles are drawn on AB, AC and BC as diameters. Find the area of the shaded region

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

14 cm

Find the circumference of the inner and the outer circles, shown in the adjoining figure? (Take π = 3.14)

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

In the given figure, O is the centre of the sector. \[\angle\]ROQ = \[\angle\]MON = 60^{°} . OR = 7 cm, and OM = 21 cm. Find the lengths of arc RXQ and arc MYN. (\[\pi = \frac{22}{7}\])

The radius of a sector of a circle is 7 cm. If the measure of the arc of the sector is 210^{°}, 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.**

The curved surface area of a cylinder is 440 cm 2 and its radius is 5 cm. Find its height.

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.

Find the area of the sector of a circle having radius 6 cm and of angle 30°. [Take π = 3.14]

In the given figure, find the area of the shaded region, if ABCD is a square of side 14 cm and APD and BPC are semicircles.

In the given figure, ABCD is a trapezium of area 24.5 cm^{2} , If AD || BC, ∠DAB = 90°, AD = 10 cm, BC = 4 cm and ABE is quadrant of a circle, then find the area of the shaded region.

The area of a square is the same as the area of a square. Their perimeters are in the ratio

In a circle of radius 21 cm, an arc subtends an angle of 60° at the centre. The length of the arc is

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 area and perimeter of the circle with the following :

Radius= 10.5 cm

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

Height = 16 cm , diameter = 24 cm

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

Find the area enclosed between two concentric circles, if their radii are 6 cm and 13 cm respectively.

The area between the circumferences of two concentric circles is 2464 cm^{2}. If the inner circle has circumference of 132 cm, calculate the radius of outer circle.

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.

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.

A wire is in the form of a circle of radius 42 cm. It is bent into a square.

Determine the side of the square and compare the area of the regions enclosed in two cases.

A 7 m road surrounds a circular garden whose area is 5544 m^{2}. Find the area of the road and the cost of tarring it at the rate of Rs.150 per sq m.

A 4.2 m wide road surrounds a circular plot whose circumference is 176 m. Find the cost of paving the road at Rs 75 m ^{2}.

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 °

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.

Find the total surface area and volume of a hemisphere whose radius is 10 cm.

A solid sphere metal is cut through its centre into 2 equal parts. If the diameter of the sphere is 3`1/3` cm , find the total surface of each part, correct to two decimal places.

The diameter of a circle is 28 cm.

Find its :

(i) Circumference

(ii) Area.

The circumference of a circular field is 308 m. Find is:

(i) Radius

(ii) Area.

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.

A wheel has a diameter of 84 cm. Find how many completer revolutions must it make to cover 3.168 km.

There are two circular gardens A and B. The circumference of garden A is 1.760 km and the area of garden B is 25 times the area of garden A. Find the circumference of garden B.

The diameters of the front and the rear wheels of a tractor are 63 cm and 1.54 m respectively. The rear wheel is rotating at `24 6/11` revolutions per minute. Find:

(i) the revolutions per minute made by the front wheel.

(ii) the distance traveled bu the tractor in 40 minutes.

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

The radius of a circle is 21 cm. Find the circumference (Take π = `3 1/7`).

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

The radius of two circles are 20 cm and 13 cm. Find the difference between their circumferences. (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.

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

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

Each side of a square is 44 cm. Find its perimeter. If this perimeter is equal to the circumference of a circle, find the radius of the circle.

Construct an angle PQR = 45°. Mark a point S on QR such that QS = 4.5 cm. Construct a circle to touch PQ at Q and also to pass through S.

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

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.

In the adjoining figure, the crescent is formed by two circles which touch at the point A. O is the centre of bigger circle. If CB = 9 cm and DE = 5 cm, find the area of the shaded portion.

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 following semicircles: Diameter = 7cm

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.

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

Find the perimeter of the given shape (Take π = `22/7`).

The radius of the wheel of a bus is 0.7 m. How many rotations will a wheel complete while traveling a distance of 22 km?

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.

49 cm

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

91 mm

The diameter of a circular well is 4.2 m. What is its circumference?

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

A ground is in the form of a circle whose diameter is 350 m. An athlete makes 4 revolutions. Find the distance covered by the athlete

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?

In the formula, C = 2πr, ‘r’ refers to

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

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

Circumferences of two circles are equal. Is it necessary that their areas be equal? Why?

The diameters of front and rear wheels of a tractor are 80 cm and 2 m respectively. Find the number of revolutions that rear wheel will make in covering a distance in which the front wheel makes 1400 revolutions.

Circumference of a circle disc is 88 cm. Its radius is ______.

Length of tape required to cover the edges of a semicircular disc of radius 10 cm is ______.

Area of circular garden with diameter 8 m is ______.

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

**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?

A circular pond is surrounded by a 2 m wide circular path. If outer circumference of circular path is 44 m, find the inner circumference of the circular path. Also find area of the path.

A dinner plate is in the form of circle. A circular region encloses a beautiful design as shown in the given figure. The inner circumference is 352 mm and outer is 396 mm. Find the width of circular design.