Question

What's my first step?

Answer 1

It is useful to determine the distance the swing is below the pivot point when it is at its highest point of travel. That distance is

... 7 m + 0.8 m - 3.4 m = 4.4 m

The the cosine of the angle of interest is

... cos(θ) = 4.4/7

... θ = arccos(4.4/7) ≈ 51.055°

The angle is about 51°.