Найдите неизвестный член пропорции 1) x : 8/9=3 : 4 2) x : 2.8=5 : 7 3) 6 : 5=9 : x 4) 12...

Question

Найдите неизвестный член пропорции
1) x : 8/9=3 : 4
2) x : 2.8=5 : 7
3) 6 : 5=9 : x
4) 12 : 7=9 : x
5) 6.5 : 5.2=x : 8
6) 12 : x=24/7 :4
7) 4.5 : 3.6=x : 4
8) 15 : 4=x : 4 / 3
9) 96 : 2.5=19.2 : x
/ это дробь : делить!
Прошу решение!

Answer 1

1) х : 8/9 = 3 : 4                              2) х : 2,8 = 5 : 7

4х = 8/9 * 3                                     7х = 2,8 * 5

4х = 8/3                                           7х = 14

х = 8/3 : 4 = 8/3 * 1/4                       х = 14 : 7

х = 8/12 = 2/3                                   х = 2

3) 6 : 5 = 9 : х                                 4)  12 : 7 = 9 : х

6х = 5 * 9                                        12х = 7 * 9

6х = 45                                            12х = 63

х = 45 : 6                                          х = 63 : 12

х = 7,5                                              х = 5,25

5) 6,5 : 5,2 = х : 8                           6) 12 : х = 24/7 : 4

5,2х = 6,5 * 8                                  24/7х = 12 * 4

5,2х = 52                                         24/7х = 48 

х = 52 : 5,2                                      х = 48 : 24/7 = 48 * 7/24 

х = 10                                              х = 14

7) 4,5 : 3,6 = х : 4                          8) 15 : 4 = х : 4/3

3,6х = 4,5 * 4                                 4х = 15 * 4/3

3,6х = 18                                       4х = 20

х = 18 : 3,6                                     х = 20 : 4   

х = 5                                               х = 5 

9) 96 : 2,5 = 19,2 : х

96х = 2,5 * 19,2

96х = 48

х = 48 : 96

х = 0,5

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