Answer:
I believe the distance is 9
The answer to this would be 40 degrees.
To solve this you need to know Pythagorean theorem.
First, EG is 24, so the halfway points are 12. Knowing Pythagorean triples, you can use 5,12,13 and 12,16,20.
DF = 5+16
DF = 21
If you don't know Pythagorean triples, I have worked it out on the image attached.