Answer:
The length of CD is 8 units
Step-by-step explanation:
<u><em>The complete question in the attached figure</em></u>
we know that
According to the Right Triangle Altitude Theorem,

substitute the given values


solve the quadratic equation by graphing
The solution is x=8 or x=-6
see the attached figure N 2
Discard the negative length.
therefore
The length of CD is 8 units