Let's draw the picture
To find the height of the tree, we have to solve the following proportion
[tex]\frac{8}{x}=\frac{12}{60}[/tex]Then, we solve for x.
[tex]\begin{gathered} 8\cdot60=12\cdot x \\ \frac{8\cdot60}{12}=x \\ x=\frac{480}{12} \\ x=40 \end{gathered}[/tex]