FIND THE MISSING NUMBER IN RATIO AND PROPORTION

Problem 1 :

Solution:

Let x be the missing term.

25 : x = 75 : 12

If two ratios are equal, then

Product of means = Product of extremes

25 ⋅ 12 = x ⋅ 75

300 = 75x

x = 4

Problem 2 :

Solution:

Let x be the missing term.

12 : 125 = x : 250

If two ratios are equal, then

Product of means = Product of extremes

12 ⋅ 250 = 125 ⋅ x

3000 = 125x

x = 24

Problem 3 :

Solution:

Let x be the missing term.

45 : 80 = 90 : x

If two ratios are equal, then

Product of means = Product of extremes

45 ⋅ x = 80 ⋅ 90

45x = 7200x

x = 160

Problem 4 :

Solution :

Let x be the missing term.

20 : x = 70 : 63

If two ratios are equal, then

Product of means = Product of extremes

20 ⋅ 63 = x ⋅ 70

1260 = 70x

x = 18

Problem 5 :

Solution :

Let x be the missing term.

15 : x = 45 : 285

If two ratios are equal, then

Product of means = Product of extremes

15 ⋅ 285 = x ⋅ 45

4275 = 45x

x = 95

Problem 6 :

Solution :

Let x be the missing term.

120 : x = 60 : 175

If two ratios are equal, then

Product of means = Product of extremes

120 ⋅ 175 = x ⋅ 60

21000 = 60x

x = 350

Problem 7 :

Solution :

Let x be the missing term.

15 : 90 = 13 : x

If two ratios are equal, then

Product of means = Product of extremes

15 ⋅ x = 90 ⋅ 13

15x = 1170

x = 78

Problem 8 :

Solution :

Let x be the missing term.

45 : x = 18 : 40

If two ratios are equal, then

Product of means = Product of extremes

45 ⋅ 40 = x ⋅ 18

1800 = 18x

x = 100

Problem 9 :

Solution :

Let x be the missing term.

24 : 100 = 60 : x

If two ratios are equal, then

Product of means = Product of extremes

24 ⋅ x = 100 ⋅ 60

24x = 6000

x = 250

Problem 10 :

Solution :

Let x be the missing term.

150 : 750 = x : 35

If two ratios are equal, then

Product of means = Product of extremes

150 ⋅ 35 = 750 ⋅ x

5250 = 750x

x = 7

Problem 11 :

Solution :

Let x be the missing term.

25 : 80 = 5 : x

If two ratios are equal, then

Product of means = Product of extremes

25 ⋅ x = 80 ⋅ 5

25x = 400

x = 16

Problem 12 :

Solution :

Let x be the missing term.

160 : x = 128 : 144

If two ratios are equal, then

Product of means = Product of extremes

160 ⋅ 144 = x ⋅ 128

23040 = 128x

x = 180