a 20 feet ladder with its base if 12 feet from the bottom of the tree.
From the figure above, we can form a right triangle with a hypotenuse of 20 and a leg of 12
Using pythagorean theorem.

where a and b are the legs of the triangle and c is the hypotenuse.
![\begin{gathered} 20^2=12^2+h^2 \\ 400=144+h^2^{} \\ h^2=400-144 \\ h^2=256 \\ h=\sqrt[]{256}=16 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/8lk6wgrji0i18n0c5np1ouvlw9ttb7pqzd.png)
The answer is h = 16 feet