While Agent Nikita was wondering as to who Agent Pathfinder was, Agent Pathfinder was chained to a wall in a triangular room. The chain was long enough for her to barely touch the other two sides of the room. She was chained to a wall that was 20 metres long while the other two walls were 11 metres long and 13 metres long respectively. Using this, deduce the longest distance that she can travel whilst chained to the wall in the room. Provide a detailed explanation along with your answer.