How many cones will engineers place in-line with the runway centerline to ensure correct placement of approach lights?

Engineers typically place seven cones in-line with the runway centerline to ensure the proper alignment and placement of approach lights. This setup is designed to provide clear guidance and enhance visibility for pilots during landing. The use of seven cones allows for a balanced and visible configuration that aids in achieving precise positioning of the lights, contributing to the overall safety and effectiveness of the approach path.