A man 1.7m tall observe a bird on top of a tree at angle of elevation of 40degree. If the bird distance between the man's head and the bird is 25m, what is the height of the tree?

Answer 1

the part of the tree above the man's eyes is h

h/25 = sin 40
h = 25sin40

tree is 1.7 + 25sin40 = 17.77

Of course, that assumes the man's eyes are on the top of his head. . .