Question

1. all of the rungs of a ladder are parallel and the top rung is perpendicular to a side of the ladder. what conclusion can be reached? all of the rungs must be of the same thickness. some of the rungs must be perpendicular to that side. all of the rungs are perpendicular to the other side. all of the rungs are perpendicular to that side.

Explanation:

If one line (the top rung) is perpendicular to a line (a side of the ladder) and all the other lines (rungs) are parallel to the first line, then by the property that if a line is perpendicular to one of two parallel lines, it is perpendicular to the other. So all rungs (parallel to the top - rung) are perpendicular to that side of the ladder. The thickness of the rungs is not related to the given parallel and perpendicular relationships. Also, it's not just some of the rungs (since all are parallel to the top - rung which is perpendicular). And we are only given information about one side of the ladder, not the other side.

Answer:

All of the rungs are perpendicular to that side.