ICSE Class 10CISCE
Share
Notifications

View all notifications

Find Two Numbers Whose Mean Proportional is 18 and the Third Proportional is 486. - ICSE Class 10 - Mathematics

Login
Create free account


      Forgot password?

Question

Find two numbers whose mean proportional is 18 and the third proportional is 486. 

Solution

Let a and b be the two numbers, whose mean proportional is 18.

`therefore "ab" = 182 => "ab" = 324 => "b" = 324/"a"` ......(i)

Now, third proportional is 486 

∴ a : b : : b : 486

⇒ b2 = 486 a

⇒ `(324/"a")^2` = 486  a

⇒ `(324)^2/"a"^2` = 486 a 

⇒ `"a"^3 = (324 xx 324)/486`

⇒ a3 = 216

⇒ a = 6

b = `324/"a" = 324/6 = 54`

Therefore, numbers are 6 and 54 .

  Is there an error in this question or solution?

APPEARS IN

 Frank Solution for Frank Class 10 Mathematics Part 2 (2016 to Current)
Chapter 9: Ratio and Proportion
Exercise 9.2 | Q: 15

Video TutorialsVIEW ALL [1]

Solution Find Two Numbers Whose Mean Proportional is 18 and the Third Proportional is 486. Concept: Proportions.
S
View in app×