Answer:
7.1 units.
Step-by-step explanation:
It is given that cd is congruent to df, e bisects df and cd= 14.2.
We have to find the measure of ef.
Using given information we get

(Measure of congruent segments are equal) ... (1)
(e bisects df) ... (2)
Using (1) and (2) we get


Hence, the measure of ef is 7.1 units.