Answer:
135°
Explanation:
The arc length is calculated as
EF = circumference of circle × fraction of circle
= 2πr ×

Given EF = 12π , then
2π × 16 ×
= 12π ( divide both sides by 2π )
16 ×
= 6 ( multiply both sides by 360 to clear the fraction )
16 ? = 2160 ( divide both sides by 16 )
? = 135°