Answer:
Step-by-step explanation:
[tex]\text{If}\ a_1,\ a_2,\ a_3,\ a_4,\ ...\ ,\ a_n\ \text{is a geometric series, then}\\\\\dfrac{a_2}{a_1}=\dfrac{a_3}{a_2}=\dfrac{a_4}{a_3}=...=\dfrac{a_n}{a_{n-1}}=r=constant[/tex]
[tex]\text{We have}\ 0.75,\ 1.5,\ 3,\ 6,\ ...\\\\\text{The common ratio}\ r:\\\\\dfrac{1.5}{0.75}=2\\\\\dfrac{3}{1.5}=2\\\\\dfrac{6}{3}=2\\\\\boxed{r=2}[/tex]