Two wheels of radii and each rotate through an angle of

MATHEMATICS · Single correct · A Level · Mathematics · Trigonometry · Trigonometry

Problem

Two wheels of radii

15\,\text{cm}

and

45\,\text{cm}

each rotate through an angle of

120^{\circ}

. What is the ratio of the arc lengths traced by points on their rims (smaller wheel : larger wheel)? (a)

2:3

(b)

3:1

(c)

1:3

(d)

1:9