Final answer:
The length of DEDE is 48 units.
Step-by-step explanation:
To find the length of DEDE, we need to first find the length of DE and then multiply it by 2. Using the given information, we know that AE = 15 and EC = 9. Since AE and EC are part of the same line, we can add their lengths to find the length of DE. DE = AE + EC = 15 + 9 = 24. Finally, to find the length of DEDE, we multiply DE by 2: DEDE = 24 * 2 = 48. So, the length of DEDE is 48 units.