Question

If a, b, c are in G.P., then 

A) c = ab 

B) a = bc 

C) b² = ac 

D) b = ac

Answer 1

Correct option is (C) b² = ac

Given that a, b, c are in G.P.

\(\therefore b=ar\)

\(c=ar^2\)

\(\Rightarrow\frac{ar^2}{ar}=\frac cb\;\&\;\frac{ar}a=\frac ba\)

\(\Rightarrow r=\frac cb\;\&\;r=\frac ba\)

\(\Rightarrow \frac cb=\frac ba\)

\(\Rightarrow\) \(b^2 = ac\)

Answer 2

Correct option is C) b² = ac