Find the third proportional of (b2 - a2) and (b2 - ab).
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. b2(b - a)/(b + a).
Calculations:
If a, b, and c are in the ratio, then
a : b : k
= a/b = b/k
(b2 - a2) and (b2 - ab) = k
According to the question;
⇒ (b2 - a2) : (b2 - ab) : k
⇒ [(b + a)(b - a)]/b(b - a) = b(b - a)/k
⇒ (b + a)/b = b(b - a)/k
⇒ k = b2(b - a)/(b + a)