Advertisements
Advertisements
Question
If x + 5 is the mean proportion between x + 2 and x + 9, find the value of x.
Advertisements
Solution
∵ x + 5 is the mean proportion between x + 2 and x + 9, then
(x + 5)² = (x + 2) (x + 9)
⇒ x² + 10x + 25 = x² + 11x + 18
⇒ x² + 10x – x² – 11x = 18 – 25
⇒ – x = – 7
∵ x = 7.
APPEARS IN
RELATED QUESTIONS
What least number must be added to each of the numbers 16, 7, 79 and 43 so that the resulting
numbers are in proportion?
Find the fourth proportion to the following:
(p2q - qr2 ), (pqr - pr2 ) and (pq2 - pr2)
Find the third proportion to the following :
`9/25` and `18/25`
If `a = (b + c)/(2), c = (a + b)/(2)` and b is mean proportional between a and c, prove that `(1)/a + (1)/c = (1)/b`.
Find the value of x in the following proportions : 2.5 : 1.5 = x : 3
If a, 12, 16 and b are in continued proportion find a and b.
If the cost of a dozen soaps is Rs 285.60, what will be the cost of 15 such soaps?
If `a/c = c/d = c/f` prove that : `(a^2)/(b^2) + (c^2)/(d^2) + (e^2)/(f^2) = "ac"/"bd" + "ce"/"df" + "ae"/"df"`
A particular high school has 1500 students 50 teachers and 5 administrators. If the school grows to 1800 students and the ratios are maintained, then find the number of teachers and administrators
Determine if the following are in proportion.
4, 6, 8, 12
