What error was made in calculating the moment at point H?

[influx]

For figure 1.2, if you take moments at the point where H acts, then you get (assuming moments are positive anti-clockwise):

-RCos(theta)(0.4) + 60(0.2) = 0

Rearranging gives:

Rcos(theta) = 30

However, according to the mark scheme (which takes moments at the point where R acts) Rcos(theta) = 60

What have I done wrong?

 

[SteamKing]

About H, there is also a moment due to the horizontal component of R.