Question

Find the fourth proportional of 14 ,7 and 10

• A. 6
• B. 7
• C. 10
• D. 5

Answer 1

The correct option is D

5

Let $x$ be the fourth proportional

Then we have 14 : 7 :: 10 : $x$

When the numbers are in proportion , then Product of means = Product of extremes

Hence $14x=7\times 10$

$x=\frac{7\times 10}{14}$

$x=5$

Hence the fourth proportional of 14 , 7 and 10 is 5