Question

Please tell this question's answer

Plz
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Answer 1

Step-by-step explanation:

Radius of the wheel =r=42 cm (given)

Circumference of wheel = Circumference of circle = 2πr=2×

7

22

×42=264

Circumference of wheel is 264 cm.

Again, distance travelled by wheel = 19.8 km=1980000 cm (Convert km into cm)

Now, number of revolutions taken by a wheel = 1980000/264=7500

Answer 2

Given:-

Radius of Wheel = 0.35 m

Distance covered by wheel = 5.5 km

Solution:-

Circumference of the wheel = 2πr

                                               = 2 × $\frac{22}{7}$ × 0.35 m

                                               = 2.2 m

Convert Distance To m from km

1 km = 1000 m

5.5 km = 5,500 m

Now, Rotations made by wheel = $\frac{5,500}{2.2}$

                                                    = 2,500 revolution

∴ Total number of Rotation done by wheel to cover 5.5 km is 2,500.

Some Important Formula:-

• Area of Circle = πr²              [ Where, π = $\frac{22}{7}$ or 3.14 ]

• Perimeter of Circle = 2πr

• Area of concentric circle = π ( R² - r² )

• Total number of revolution = $\frac{Distance covered by wheel}{Circumference of wheel}$

• Distance covered by wheel = Total number of revolution × Circumference of wheel