Circumference is 2πr or πd. So for part 1 the diameter = 9in. Plug in 9 into the πd formula. π*9 = 9π in. ≈ 9*(22/7) ≈ 28.29in
For part 2 (from what I can see) they want you to find the same circumference in centimeters(cm) and use 22/7 for π so first convert the radius to cm. 9 in = 9*2.54 = 22.86cm Next plug in the values into the Circumference formula: π*d (22/7)*(22.86) ≈ 71.85cm
