Question

What is the length of the arc shown in​ red?

Answer 1

≈ 18.8 cm

Explanation:

The arc length is calculated as

arc = circumference of circle × fraction of circle

The central angle is equal to the arc subtending it, that is 60°

arc = 2πr ×
`(60)/(360)`

= 2π × 18 ×
`(1)/(6)`

= 36π ×
`(1)/(6)`

= 6π ≈ 18.8 cm ( to 1 dec. place )