Solution

First we create an equation with the angle (we'll can A) in it.

SinA = l/2.11 m
SinA (2.11 m) = 1

Now we plug it into the torque equation and solve for A (or the angle value).

Torque = F * l
76 N*m = 40 N (SinA)(2.11 m)
76 N*m = 84.4 N*m (SinA)
0.9 = SinA
64 degrees = A