Q8 of 176 Page 20

Find three numbers in G.P. whose product is 729 and the sum of their products in pairs is 819.

Let the three numbers be .


∴ According to the question


⇒ …(1)


From 1 we get


⇒ a3 = 729


∴ a = 9.


⇒


⇒ a + ar + a2 = 819


Substituting a = 9 in above equation we get


⇒ 9 + 9r + 81 = 819


⇒ 9r = 729


⇒ r = 81


∴ are the three numbers.


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