A 6-foot tall man is standing near a tree on level ground as shown in the picture above.if the man's shadow is 4feet long, how many feet tall is the tree? The only thing it show's in the picture is 18feet! So?

The sun is in such a position that the man's shadow (4ft) is equal to two-thirds of his actual height (6ft). Using the same scale, it can be taken that the tree's shadow of 18 feet is equal to two-thirds of the tree's actual height, thus :-
18 divided by 2 = 9.

9 x 3 = 27

So the tree is 27 feet high.