Let the height of the beanstalk be h
from the diagram,
[tex]\begin{gathered} \tan \text{ }\theta=\frac{15}{10}=\text{ 1.5} \\ \theta=\text{ }\tan ^{-1}1.5=56.3^0 \end{gathered}[/tex]Also,
[tex]\begin{gathered} \tan \text{ }\theta=\frac{h}{100} \\ 1.5=\frac{h}{100} \\ h=1.5\text{ x 100} \\ h=150\text{ ft} \end{gathered}[/tex]