Correct. A right triangle is formed in the picture, with the length of the side opposite the angle $\displaystyle\theta\usepackage{cmbright}\Huge\$ equal to 50 feet and the length of the side adjacent to angle $\displaystyle\theta\usepackage{cmbright}\Huge\$ equal to 40 feet. So you can use the tangent function to set up an equation:

$\displaystyle{\tan{\theta}}=\frac{{50}}{{40}}={1.25}\usepackage{cmbright}\Huge\$

You want to know the value of $\displaystyle\theta\usepackage{cmbright}\Huge\$ . That is, you want to know the measure of an angle that gives you a certain tangent value. This means you need to find the inverse tangent:

$\displaystyle\theta={{\tan}}^{{-{{1}}}}{1.25}={51.340}{\ldots}^{\circ}\approx{{51.3}}^{\circ}\usepackage{cmbright}\Huge\$