Answer
$81:1$
Work Step by Step
The given values are
$r_l=36\;in.$
$r_s=4\;in.$
Formula for the mechanical advantage is
$\Rightarrow MA=\frac{r_l^2}{r_s^2}$
Substitute all the values.
$\Rightarrow MA=\frac{(36\;in.)^2}{(4\;in.)^2}$
Cross multiply.
$\Rightarrow MA=\frac{81}{1}$
Hence, the $MA$ is $81:1$.
