Parallel lines never intersect, but they must be in the same plane. The definition does not require the undefined term point, but it does require plane. Because they intersect, perpendicular lines must be coplanar; consequently, plane is not required in the definition.
the line is worth 180 degrees. subtract 90 and 47 because that is part of the 180. your left with 43 degrees which is what is missing. hope this helps!