Question

The third term of a G.P is the square of the first term. If the second term is $8$,find its sixth term.

Answer 1

Let the G.P be $a,ar,a{r}^2,....$

$a{r}^2=a^2$

$\therefore a=r^2$

$ar=8$

$r^3=8$

$\Rightarrow r=2,a=4$

$a{r}^5=4\times 2^5=128$

$\therefore$ sixth term is $128$