If chord ab is congruent to chord cd, then what must be true about ef and eg?

They are the same length

Step-by-step explanation:

To solve this, let's draw lines AE and DE. Since AB = CD, GD = FA. Using the Pythagorean Theorem, we have that EF^2 = AE^2-FA^2 and EG^2 = DE^2-DG^2. Because AE and DE are radii of the same circle, they are equal, and since DG = FA, we can find that EG^2 = AE^2-FA^2 too, so this means that they are the same length.

I originally put FA switched, so it was an acronym for a bad word. Good thing I found out!