If a wheel has diameter 42 cm, then how far does the wheel go (in metres) in 12 revolutions? (Take $\pi=\frac{22}{7}$)

15.84

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