Q5 of 59 Page 77

a, b ,c are in continued proportion. If a = 3 and c = 27 then find b.

Given: a, b, c are in continued proportion.


Three numbers ‘a’, ‘b’ and ‘c’ are said to be continued proportion if a, b and c are in proportion,


i.e. a:b∷b:c


or b2 = ac


Here, a = 3, c = 27


∴ (b)2 = 3 × 27


⇒ b2 = 81


⇒ b = √81 = 9


∴ b = -9 or 9


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