9) pi/3 = 180 /3 = 60⁰
the other angle = 90-60=30⁰
10) 2pi/9 = 360/9 = 40⁰
the other angle = 90+40=130⁰
11) arc length = 2pi * r * (θ/360)
= 2pi * 16 * (270/360)
= 75.4 km
12)arc length = 2pi * r * (θ/360)
3 * 180/4 = 135⁰
135/360 =0.375
2pi * 6 * 0.375 =14.13 in
13) arc length = 2pi * r * (θ/360)
= 9 *2pi *(255/360) =40.05 mi
14)arc length = 2pi * r * (θ/360)
=23.56 mi
