Answer:
4 units
Step-by-step explanation:
Angle bisector property says that an angle bisector of a triangle will divide the opposite side into two segments that are proportional to the other two sides of the triangle.
By angle bisector property,
[tex]\dfrac{EK}{KF}=\dfrac{DE}{DF}\\ \\\dfrac{2}{5}=\dfrac{DE}{10}\\ \\DE=\dfrac{2\cdot 10}{5}=4\ units[/tex]
