402. 80/60 = x/3
80 · 3 ։ 60 = 4ժ
403. ա. 5/10 = x/8
5 · 8 ։ 10 = 4
բ.
404. 8/14 = 63/x
14 · 63 : 8 = 110,25
405. 8/3 = x/6
8 · 6 : 3 = 16
406. 8/15 = 30/x
15 · 30 ։ 8 = 56,25
407. 80/60 = x/720
720 · 80 ։ 60 = 960
408. ա. 60/80 = x/8
60 · 8 ։ 80 = 6
բ. 4/5 = x/10
4 · 10/5 = 8
409. 1/4000 = 2,5 /x
4000 · 2,5 : 1 = 10000
410. ա. x/60 = 40/30
60 · 40 : 30 = 80
բ. 60/50 = x/1
60 · 1 = 60
60 : 50 = 1,2
411. 60/50 = x/40
60 · 40 = 2400
2400 : 50 = 48
412. ա. 6/27 = 4/x
27 · 4 = 108
108 : 6 = 18
բ.
413. ա. 6/10 = 18/x
10 · 18 = 180
180 : 6 = 30
414. 6/9 = x/18
6 · 18 = 108
108 : 9 = 12
415. ա. x/6 = 5/3
5 · 6 = 30
30 : 3 = 10
10 — 6 = 4
բ. x/2 = 10/4
2 · 10 = 20
20 : 4 = 5
5 — 2 = 3
416. x/20 = 30/5
20 · 30 = 600
600 : 5 = 120