size:21 yards are about 13.5cm long, 22 yards are about 14cm long, 23 yards are about 14.5cm long, 24 yards are about 15cm long, 25 yards are about 15.5cm long, 26 yards are about 16cm long, 27 yards are about 16.5cm long, 28 yards are about 17cm long, 29 yards are about 17.5cm long, 30 yards are about 18cm long
