Question

find the fourth proportional of 2,5\7,14\15.​

Answer 1

Finding the 4th proportional is an exercise in executing "product of means"="product of extremes"

For example on problem 1, you would solve

1/9:1/6::1/3:x

Since the product of the means is the product of the extremes, you would get

1/6×1/3=1/9×x

Solving for x gives x=12.

The second example is similar. The correct answer should be 2. (Obtained by setting 9.1x=(6.5)(2.8) )

Answer 2

Answer:

Step-by-step explanation:

let fourth proportional be m

2:5/7::14/15:m

now,

2*m = 5/7*14/15

2*m 4/21

m = 4/21*2

m = 2/21

∴ m  = 2/21 (fourth proportional)