练习二十四,（选自教材,P104-106,）,15,0,17.5,5,20,12.5,22.5,15,25,17.5,27.5,20,30,25,32.5,25,27.5,20,25,15,20,10,17.5,3,54.5,51.4,71.4,77.2,88.0,（,2,）平原：,96018.8%=180.48,（,km,2,）,盆地：,96012%=115.2,（,km,2,）,丘陵：,9609.9%=95.04,（,km,2,）,山地：,96033.3%=319.68,（,km,2,）,高原：,96026%=249.6,（,km,2,）,（,1,）,(2391+2511+1636+1594+1482+1439+704+928+3093)9,1753.11(,时,),（,2,）,9282511,36.96%,可能发生,一定发生,不可能发生,可能发生,红球,黄球,