Question

please solve it . with process. ​

Answer 1

1) The length of a piece of wire is 79.2 cm. If the wire is bent in the form of a circle, then find the radius of the circle so formed.

Answer :-

• Length of a piece = 79.2 cm

• Circumference Of circle = Length of a piece

• Circumference Of circle = 79.2 cm

• Radius = ?

We know that,

• Circumference Of Circle = 2 × π × r

• 79.2 = 2 × π × r

• 79.2 = 2 × 22/7 × r

• r = 79.2 × 2 / 2 × 22

• r = 158.4 / 44

• r = 3.6

Radius = 3.6 cm

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2) A piece of wire is in the form of a rectangle which is 30.9 cm long and 19.7 cm wide. The wire is straightened and then bent in the form of a circle. Find the radius of the circle so formed.

Answer :-

• Length = 30.9 cm

• Breadth = 19.7 cm

• Radius = ?

We know that,

Perimeter Of Rectangle = 2 × ( Length + Breadth)

Perimeter Of Rectangle = 2 × ( 30.9 + 19.7 )

Perimeter Of Rectangle = 2 × ( 30.9 + 19.7 )

Perimeter Of Rectangle = 2 × 50.6

Perimeter Of Rectangle = 101.2

Perimeter Of Rectangle = 101.2 cm

We know that,

• Circumference Of Circle = 2 × π × r

• 101.2 = 2 × π × r

• 101.2 = 2 × 22/7 × r

• r = 101.2 × 2 / 2 × 22

• r = 202.4 / 44

• r = 4.6

Radius = 4.6 cm

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3) A piece of wire when bent in the form of a circle, the radius of the circle becomes 13.3 cm. If the same piece of wire is bent in the form of a rectangle 29.3 cm long, what will be the width of the rectangle so formed ?

Answer :-

• Radius of circle = 13.3 cm

• Length of rectangle = 29.3 cm

• Breadth = ?

We know that,

• Circumference Of Circle = 2 × π × r

• Circumference Of Circle = 2 × 22/7 × 13.3

• Circumference Of Circle = 83.57

Circumference Of Circle = 83.57 cm

We know that,

• Perimeter Of Rectangle = 2 × ( Length + Breadth)

• 83.57 = 2 × ( 29.3 + Breadth )

• 83.57 = 78.6 + 2 × Breadth

• 2 × Breadth = 83.57 - 58.6

• 2 × Breadth = 24.97

• Breadth = 24.97 / 2

• Breadth = 12.485

Breadth = 12.48 cm

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4) The radius of a wheel is 25 cm. Find the distance that can be covered by the wheel in 40 revolutions. (Take π = 3.14)

Answer :-

• Radius = 25 cm

• Revolution = 40

• π = 3.14

• Circumference Of Circle = Circumference Of Wheel

• Distance Covered = ?

We know that,

• Circumference Of Circle = 2 × π × r

• Circumference Of Circle = 2 × 3.14 × 25

• Circumference Of Circle = 6.28 × 25

• Circumference Of Circle = 157

Circumference Of Wheel = 157 cm

We know that,

• Revolution = 40

• Circumference Of Wheel = 157 cm

• Distance Covered = Revolution × Circumference Of Wheel

• Distance Covered = 40 × 157

• Distance Covered = 6280

Distance Covered = 6280 cm

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5) The radius of the wheel of a vehicle is 35 cm. Find the number of revolutions that the wheel will make to cover a distance of 22.77 km

Answer :-

• Radius = 35 cm

• Distance = 22.77 km

• Revolution = ?

We know that,

• Circumference Of Circle = 2 × π × r

• Circumference Of Circle = 2 × 22/7 × 35

• Circumference Of Circle = 2 × 3.14285714 × 35

• Circumference Of Circle = 220

Circumference Of Wheel = 220 cm

We know that,

• Distance = 22.77 km = 2277000 cm

• Circumference Of Wheel = 220 cm

• Revolution = Distance / Circumference Of Wheel

• Revolution = 2277000 / 220

• Revolution = 10350

Revolution = 10350