解:根据已知得出:AB∥DZ∥EF,∴ CB CZ = AB QZ , FG ZG = EF QZ ,∵AB=1.5m,EF=1.7m,FG=1.7m,ZF=BZ+1.3,BC=1,∴ 1 1+BZ = 1.5 QZ , 1.7 1.7+1.3+BZ = 1.7 QZ ,∴QZ=1.5+BZ,∴ 1.7 3+BZ = 1.7 1.5+BZ ,解得:BZ=3,∴QZ=6m.故答案为:6.