If CD is 10, ED is 1/2 that, or 5. Use the pythagorean theorem for triangle DEA to find length AE.
a² + b² = c²
a² + 5² = 6²
a² + 25 = 36
a² = 11
a = √11
So AE is √11 cm or 3.3 cm
I hope this helps!