Question

A circle C₁ of radius b touches the circle x² + y² = a² externally and has its centre on the positive x-axis; another circle C₂ of radius c touches the circle C₁ externally and has its centre on the positive x-axis. Given a < b < c, then the three circles have a common tangent if a, b, c are in –

• A. A.P.
• B. G.P.
• C. H.P.
• D. None of these

Answer 1

Answer: (B)

G.P.

Answer 2

$\frac{a}{x}$ = $\frac{b}{x + a + b}$ = $\frac{c}{x + a + 2b + c}$eliminate x