The Divide and conquer methodology is an effective troubleshooting approach because it allows the technician to break down a large problem into smaller, more manageable parts. By isolating segments of the network, the technician can focus on each part individually, which simplifies the process of identifying and resolving issues. This strategy is especially useful when dealing with complex network environments, as it helps in pinpointing exactly where a problem starts, which may not be immediately apparent when looking at the network as a whole.