See the attached diagram.
In the right triangle, x is opposite the 23.6 degree angle, and the adjacent side is 250 m. This suggests using the tangent ratio.
[tex]\frac{x}{250}=\tan 23.6 ^\circ \\ x=250 \cdot \tan 23.6^\circ \approx 109.2[/tex]
Finally, to get the height of the tree, add Sarah's height, 1.5 m.
The tree is approximately 110.7m tall.
