Step 1: Understand what it means for \( a, b, c \) to be in G.P.
If three numbers are in Geometric Progression, then:
\[ \frac{b}{a} = \frac{c}{b} \]
Step 2: Cross-multiply the equation.
\[ b^2 = a \cdot c \]
Step 3: Divide both sides by \( b \cdot c \)
\[ \frac{b^2}{b \cdot c} = \frac{a \cdot c}{b \cdot c} \]
\[ \frac{b}{c} = \frac{a}{b} \]
Step 4: Hence, we get:
\[ \frac{a}{b} = \frac{b}{c} \]