Correct. The arc determined by $\displaystyle\angle{G}{O}{H}\usepackage{cmbright}\Huge\$ has length $\displaystyle{s}={36}\usepackage{cmbright}\Huge\$ inches. The radius $\displaystyle{r}={1.5}\usepackage{cmbright}\Huge\$ feet. You need to have the two measurements in the same units, so you must convert one of them:

$\displaystyle{r}={1.5}\ \text{ ft}={1.5}\ \text{ ft}\cdot\frac{{{12}\ \text{ in}}}{{{1}\ \text{ ft}}}={18}\ \text{ in}\usepackage{cmbright}\Huge\$

Now substitute these lengths into the formula: $\displaystyle\theta=\frac{{s}}{{r}}=\frac{{{36}\ \text{ in}}}{{{18}\ \text{ in}}}={2}\usepackage{cmbright}\Huge\$