Question

12 : 20 :: 18 : ?
$12 : 20 :: 18 : ?$

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Answer 1

Answer:

30

Step-by-step explanation:

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Answer 2

Answer:

12 : 20 :: 18 : 30

Step-by-step explanation: Here given three numbers are 12,20,18.

Here we want to find fourth proportion.

But now question is how can we find fourth proportion?

By one example we can understand the problem,

We are taking three numbers 2 and 3 and 4. Let fourth proportion of 2,3 and 4 be x.

So we can write 2 : 3 :: 4 : x

So,

$\frac{2}{3} = \frac{4}{x}$

By Cross multiplication,

$2x = 4 \times 3 \\ 2x = 12 \\ x = \frac{12}{2} \\ x = 6$

So fourth proportion of 2,3 and 4 is 6.

Here given 12 : 20 :: 18 : ?

Let their fourth proportion be y.

So,

$\frac{12}{20} = \frac{18}{y}$

By Cross multiplication,

$12y = 18 \times 20 \\ y = \frac{18 \times 20}{12} \\ y = \frac{3 \times 20}{2} \\ y = 30$

Required fourth proportion is 30.

Know more about Proportion :

1) https://brainly.in/question/36350

2) https://brainly.in/question/6662303