Ratio and proportion lang yan. Two right triangle.
1. Where at 40 degree distance from base of the pole (assuming horizontal plane at x axis) lets say that point from pole base is mark as point "r". And pole base is 0.
2. And 80 ft nearer the pole seeing the highest point of the pole its angular degree is 65 degree. Mark as point " x".
/ 40 d /65d I
r x 0( base)
3. where distance from r to x = 80 ft. Point r = x + 80ft = adjacent side
ratio and proportion on right triangle point x, 0, p then x. And right triangle point r,0,p then r.
Just solve the other unknown. Goodluck.