One complete turn equals circumference 2 x (22/7) x 28 = 176 cm = 1.76 m. For 1 km (100,000 cm), turns = 100000 / 176 = 568.18, which is approximately 568 full turns.
The wheel of a car has an outer radius of 28 cm. Calculate how far the car travels after one complete turn of the wheel and how many times the wheel turns during a journey of 1 km.
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Radius of the car wheel r = 28 cm.
Distance travelled in one complete turn = circumference of wheel:
Circumference = 2 x π x r = 2 x (22/7) x 28 = 2 x 22 x 4 = 176 cm = 1.76 m.
Total distance of journey = 1 km = 1000 m = 100,000 cm.
Number of turns = Total distance / Distance per turn
= 100000 / 176 = 12500 / 22 = 6250 / 11 ≈ 568.18.
Therefore, the wheel turns approximately 568 times during the 1 km journey.
For more NCERT Solutions of Class 9 Ganita Manjari Chapter 6 Measuring Space: Perimeter and Area Question Answer (2026-27)
https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-6/