Question

what is fourth proportion to 3,7 and 9 ?

Answer 1

Let the fourth proportional be x.

Now,

3/7 = 9/x

3x = 7 x 9

3x = 63

x = 21

Req number = 21

Answer 2

Answer:

It is 21.

Step-by-step explanation:

3 : 7 :: 9 : x

3x = 7×9

3x = 63

x = 63÷3

x = 21