Ok, going to assume that the angle of 60 degrees is between the wall and the ladder, yes?

First thing, draw a picture and mark in the information you have. The 6m ladder becomes the hypotenuse of the triangle because it's opposite the right angle. The angle of sixty degrees is important - it's the angle you use that decides which side is the opposite and which side is the adjacent. It's the adjacent if it helps form the angle, and it's the opposite if you can draw an arrow across the triangle to point at the side.

If the angle was between the foot of the ladder and the ground, this next bit is going to be wrong!

If we call the distance between the foot of the ladder and wall d... then we find that we have a hypotenuse and an unknown opposite side. Opposite and hypotenuse, that tells us it's sin that we use...

so we write: (and please excuse the lack of symbols!)

sin 60 = d/6 (that is, opposite side over adjacent side)

Next step is to simply rearrange the equation to get d by itself... you undo dividing by 6 by multiplying both sides by 6 and end up with:

d = 6 * sin 60

and off you go.

If the angle was between the foot of the ladder and the floor, then the unknown side (d) is actually the adjacent and you'd go with cos...

cos 60 = d/6, etc.

Hope that helps clarify things a little more.

BW