Call the angle of elevation A. The ramp is the hypotenuse of a right triangle with acute angle A. The length of the side opposite angle A equals the height above the ground of the other end of the ramp, so $\displaystyle{o}={1}\usepackage{cmbright}\Huge\$ . The hypotenuse equals the distance along the ramp to the building, so $\displaystyle{h}={5}\usepackage{cmbright}\Huge\$ . This means that:

$\displaystyle{\sin{{A}}}=\frac{{o}}{{h}}=\frac{{1}}{{5}}={0.2}\usepackage{cmbright}\Huge\$

So: $\displaystyle{A}={{\sin}}^{{-{1}}}{0.2}\approx{{11.53695903}}^{\circ}\approx{{12}}^{\circ}\usepackage{cmbright}\Huge\$