Question

EXERCISE 21B
1. Find the circumference of a circle whose radius is
(1) 28 cm

(2) 10.5 cm

(3)3.5cm

2. Find the circumference of a circle whose diameter is
(1) 14 cm

(2) 35 cm

(3)10.5cm

3. Find the radius of a circle whose circumference is 176 cm.

4. Find the diameter of a wheel whose circumference is 264 cm.

5. Find the distance covered by the wheel of a car in 500 revolutions if the diameter of the wheel is 77cm


6. The diameter of the wheel of a car is 70 cm. How many revolutions will it make to travel 1.65km?

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Answer 1

Answer:

Step-by-step explanation:

{1}circumference of a circle whose radius is

1)176cm

2)66cm

3)22cm

{2}the circumference of a circle whose diameter is

1)44cm

2)110cm

3)33cm

{3} R =28.01cm

{4} D= 84cm

{5}  THE DISTANCE COVERED BY THE WHEEL= 121000.

{6}

1.65 km = 1.65 ×1000×100 cm

             = 165000 cm  

now, radius = diameter/2

          = 70/2

          =35 cm

now, circumference = 2π r

                                = 2×(22/7)×35

                                = 220 cm

it means, 220 cm = 1 revolution

      then, 165000 cm = 165000/220

                                  = 750 revolution