Answer:
Length of arc AD = 15.7 cm
Explanation:
Length of arc =

Here, θ = Central angle subtended by the arc
r = radius of the circle
From the picture attached,
Central angle subtended by arc AD = 360° - (180° + 66.4°)
= 113.6°
Length of arc AD =

=

= 15.655 cm
≈ 15.7 cm
Length of arc AD = 15.7 cm