To calculate the tension in a rope holding a chandelier, one must consider the weight of the chandelier and the angles formed by the chains. The chandelier weighs 45 kg, which translates to a force due to gravity that needs to be balanced by the tensions in the ropes. A free body diagram is essential for visualizing the forces at play and determining the tension in the 5 m rope. Participants emphasize the importance of showing initial efforts in problem-solving to receive effective assistance. The thread was ultimately locked to encourage better preparation and engagement from the original poster.