We know that in a circle of radius r unit, if an arc of length l units subtends an angle θ radian at the centre, then θ=l/r
Therefore, for r=100cm, l=22cm, we have
θ=22/100 radian = 180/π × 22/100 degree = 180 × 7 × 22 / 22 × 100 degree = 126/10 degree = 12.6 degree = 12°36', [∵ 1° = 60']