The height of the tree is x feet based on the diagram.

Similar triangles have side lengths that are proportional so we can write:

\(\displaystyle{\frac{{{A}{B}}}{{{D}{E}}}}={\frac{{{B}{C}}}{{{E}{C}}}}\)

\(\displaystyle{\frac{{{x}}}{{{4}}}}={\frac{{{9}+{6}}}{{{6}}}}\)

\(\displaystyle{\frac{{{x}}}{{{4}}}}={\frac{{{15}}}{{{6}}}}\)

\(\displaystyle{x}={\frac{{{15}}}{{{6}}}}{\left({4}\right)}\)

\(\displaystyle{x}={10}\)

So, the height of a tree is 10 ft.

Similar triangles have side lengths that are proportional so we can write:

\(\displaystyle{\frac{{{A}{B}}}{{{D}{E}}}}={\frac{{{B}{C}}}{{{E}{C}}}}\)

\(\displaystyle{\frac{{{x}}}{{{4}}}}={\frac{{{9}+{6}}}{{{6}}}}\)

\(\displaystyle{\frac{{{x}}}{{{4}}}}={\frac{{{15}}}{{{6}}}}\)

\(\displaystyle{x}={\frac{{{15}}}{{{6}}}}{\left({4}\right)}\)

\(\displaystyle{x}={10}\)

So, the height of a tree is 10 ft.