Question

find the fourth proportional to:
i) 30,105,42
ii) 4,6,8.
iii) 7,14,16.
iv) 1/3,1/5,1/7.


NOTE: i want step by step answers​

Answer 1

Answer:

42,12,7

Let the fourth proportional be x

Then 42,12,7,x are in proportion

Using the cross product rule

Product of extremes = Product of means

42×x=12×7

x=

42

12×7

x=

42

84

x=2