Answer:
17.3 m
Step-by-step explanation:
If t is the height of the tree, then the length of the shadow is ...
shadow length = t/tan(α)
where α is the angle of elevation. The difference in shadow lengths is ...
20 m = t/tan(30°) -t/tan(60°) = t(√3 -1/√3)
t = (20 m)/(2/√3) = 10√3 m ≈ 17.3 m
The tree is about 17.3 meters high.
