See section 12.4.4 for points of intersection of objects in space.
The inter command takes two geometric objects as arguments and returns a list of the points of intersection of the two objects.
The inter command optionally takes a point as a third argument. In this case, inter returns the point of intersection closest to this argument.
For example, entering
draws the points at (1,0) and (0,1).
To get just one of the points, use the usual list indices.
draws just one of the points.
To get the point closest to (0,1/2), enter