Final answer:
To find the length of line segment DF, add DE (5) and EF (6) together, resulting in DF being 11 units long.
Step-by-step explanation:
Given that point E is on line segment DF, with DE equals 5 and EF equals 6, to determine the length of DF, we simply add the lengths of DE and EF together. From the properties of line segments, if a point lies between two points on a line segment, the sum of the lengths of the two smaller segments equals the length of the entire segment.
The length of DF is therefore the sum of the lengths DE and EF:
DF = DE + EF
DF = 5 + 6
DF = 11