If a wheel has diameter 42 cm, then how far does the wheel go (in metres) in 12 revolutions? (Take $\pi=\frac{22}{7}$)
Answer & explanation
Correct answer: option 3
We know that,
Circumference = 2πr
We have,
Diameter = 42 cm
then the radius = 21 cm
Number of revolution = 12
Circumference = 2πr
Circumference = 2 × \(\frac{22}{7}\)× 21 = 2 × 22 × 3 = 132 cm
We know that,
Total distance = Number of revolution × Circumference
Total distance = 12 × 132 = 1584 cm or 15.84 m