This is a basic question from ML aggarwal book of class 10th, chapter 7, ratio and proportion., ICSE board

In this question we have been given that (11a2 + 13b2) (11c2 – 13d2) = (11a2 – 13b2) (11c2 + 13d2), and. We have to prove that a: b :: c: d.

Question 6, 7.3

Solution:It is given that

(11a

^{2}+ 13b^{2}) (11c^{2}– 13d^{2}) = (11a^{2}– 13b^{2}) (11c^{2}+ 13d^{2})We can write it as

Therefore, it is proved that a: b :: c: d.