Drawing a sketch, placing Charles at point C, the base of the building immediately below Charlie at point Z, the car at point Y, and the truck at point X.
Call the distance from Y to Z 'c', the distance from to Z 'c + 800', and the height of the building 'h'.
Triangle CZY is a right triangle with Z the right angle and angle C = 66o ---> tan(66) = x / h
Triangle CZX is a right triangle with angle XCZ = 80o ---> tan(80) = (x + 800) / h
We now have: tan(66) = x/h ---> x = h·tan(66)
tan(80) = (x + 800)/h ---> x + 800 = h·tan(80) ---> x = h·tan(80) - 800
Combining these two equations: h·tan(66) = h·tan(80) - 800
h·tan(66) - h·tan(80) = -800
h(tan(66) - tan(80)) = -800
h = -800 / (tan(66) - tan(80))
h = 233.6'