In circle D, ∠EDH ≅ ∠EDG.

Circle D is shown. Line segment F H is a diameter. Line segments D E and D G are radii. Lines are drawn from point E to point G and from point E to point H to form secants. The length of E J is 4 and the length of E H is 9. The measure of arc F E is 57 degrees and the measure of arc F G is 66 degrees.

What is the length of JG?

4 units
5 units
6 units
9 units