Question

Find the fourth proportional to 13, 4, 39​

Answer 1

Answer:

12

Step-by-step explanation:

13:4: :39:?

Let ? be =x

Now, 13/4=39/x

x=39/13×4

x=3×4

x=12

Answer 2

Answer

Fourth Proportion is 12

Step-by-step explanation

Let the Fourth Proportion be x

⇒ 13 : 4 :: 39 : x

⇒ 39 × 4 = 13x                  [∵ Product of Means = Product of Extremes]

⇒ 156 = 13x

⇒ x = 156/13

⇒ x = 12