Bunk for tool

Triganomitry? - how does a theodolite work

Trigonomitry see question below?
The inspector uses his theodilite some distance south of the building and noted that the elevation angle degres.He from the top of the building 42 then moves 98meters west and the elevation angle is 36 degrees now theodolite is 1.5 m above the height of the building groung . find with the drawing to scale
Can anyone help with what I am working with formulas, and I get a response from 122m of which 1.5 is this the right and define how this scale
If you can not even go through it step by step how to use and also how to solve EQUAST as