Answer:
The length of AE is 8 units .
Explanation:
Now by using the midpoint theorem .
This theorem states that the segment joining two sides of a triangle at the midpoints is parallel to the third side and is half the length of the third side .
Thus
BD is the segment joining midpoints B and D of triangle and is parallel to side AE.

BD = 4 units
Putting in the above

AE = 4 × 2
AE = 8 units
Therefore the length of AE is 8 units .