72km/h=72×1km/h=72× 1000m 3600s =20m/s.15m/s=15×1m/s=15× 1 1000 km 1 3600 h =54km/h.180m/min=180×1m/min=180× 1m 60s =3m/s.340m/s=340×1m/s=340× 1 1000 km 1 3600 h =1224km/h.故答案为:20;54;3;1224.