Not enough data given here. Incomplete question.
Answer:
34.64 ft
Step-by-step explanation:
Distance from the building = 20 ft
Angle of inclination = π/3 radians
The tangent of the angle of inclination must equal the height of the building divided by the distance of the observer from the building:

The building is 34.64 ft tall
find three consecutive number whose sum shall equal 45
Answer: 1,3,5
Step-by-step explanation: