2 m from the top of the tree is an altitude of about 4 m (more precisely, 3.985 m, which is 4 m multiplied by the cosine of 5 degrees). This altitude is equal to the length of the pole multiplied by the sine of 60 degrees.In other words, the length of the pole is

4 m) cos(5) / sin(60) = 4.6012... mTo the nearest meter, that's 5 m.