It's very simple...
Let's find the angle using the tree height and the length of the shadow.
Tree height Ht = 30 ft
Length of the shadow is 65 ft
Length of the tree shadow is 65 ft - 25 ft = 40 ft
Angle A = ? tan(A) = 30/40 ≈ 36.87°
Pole height Hp = tan(A) * 65 = 48.75 ft