Considering N as Nadia's position, T as the top of the tower and O its base, we have a right triangle NOT, where NO = 60 ft and the angle associated to the vertex N is 30°.
Therefore, the height of the tower, TO, is given by:
[tex]\begin{gathered} \tan30\degree=\frac{TO}{NO} \\ TO=\tan30\degree\cdot NO \\ TO\approx0.577\cdot60 \\ TO\approx34.6\text{ ft} \end{gathered}[/tex]