Answer:
1st
length of arcAB=80/360×2π×4=16π/9
2nd
length of arcAB=45/360×2π×9=9π/4
3rd
length of arcAB=60/360×2π×6=2π
4th
length of arcAB=52/360×2π×7=13π/35
5th
length of arcAB=72°/360×2π×5=18π/25
6th
length of arcAB=90/360×2π×4=2π
your answer is 3rd and 6th.
