Correct. Call the angle of elevation A. The ramp is the hypotenuse of a right triangle with acute angle A, so $\displaystyle{h}={8}.\usepackage{cmbright}\Huge\$ The length of the side opposite angle A equals the height above the ground of the other end of the ramp, so $\displaystyle{o}={3}.\usepackage{cmbright}\Huge\$ This means that:

$\displaystyle{\sin{{A}}}=\frac{{o}}{{h}}=\frac{{3}}{{8}}={0.375}\usepackage{cmbright}\Huge\$

So: $\displaystyle{A}={{\sin}}^{{-{1}}}{0.375}={{22.02431284}}^{\circ}\approx{{22}}^{\circ}\usepackage{cmbright}\Huge\$