To determine the approximate length of the dead-end corridor in the given figure, we must identify the corridor section that meets the definition of a dead-end. A dead-end corridor is a hallway with only one way out, posing a potential risk in case of an emergency due to a lack of alternative egress routes.

Based on the image provided:

Locate the Dead-End Corridor:The dead-end corridor would be the section of the hallway that does not provide an exit in two directions.

Measure the Length:The length of this corridor is the distance from the point where it ends (a wall or another impassable barrier) to the nearest point where it provides access to a way out or another direction.

From the image, the corridor to the left of rooms 103, 104, and 105 appears to be a dead-end corridor.

Approximate Length Calculation:

The length of the dead-end corridor is indicated in the diagram as "31 ft 6 in. (9.6 m)".