10,5: 8 = 40: x solution: x: 3/4 =1/5: 2/52/5x = 3/4 *1/5x = 5/81.5: x =

x:2=2.5:5

1 1, solution: let the model height xm35: x = 500:1500x = 35x = 35/500x = 0. 070.07m = 7cm.

12*、3*40=8* 15 8:3=40: 15 3:8= 15:40 3: 15=8:40 15:3=40:8 40: 15=8:3 15:40=3:8 8:40=3: / kloc-0/5 40:8= 15:3 2.5*0.4 =0.5*2 0.5:2.5=0.4:2 2.5:0.5=2:0.4 2.5:2=0.5:0.4 2:2.5=0.4:0.5 0.4:2=0.5:2.5 2:0.4=2.5:0.5

0.5:0.4=2.5:2 0.4:0.5=2:2.5 13*、5/8=5/8 0.63: 1=6.3: 10

39. Fill in all 25.