Answer:
90 ft
Explanation:
Given,
The 6 ft tall man casts 4 ft long shadow,
So, the ratio of the height of the man and its shadow =
=
Now, suppose the height of the tree that casts the shadow of 60 ft long is h ft,
So, the ratio of the height of tree and its shadow =

At the same time,


Hence, the height of the tree is 90 ft