What is the length of the arc shown in red?

Answer:
≈ 18.8 cm
Step-by-step 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 × [tex]\frac{60}{360}[/tex]
= 2π × 18 × [tex]\frac{1}{6}[/tex]
= 36π × [tex]\frac{1}{6}[/tex]
= 6π ≈ 18.8 cm ( to 1 dec. place )