Answer:
Solution: Let ∠DCE=x and ∠ACD=y, then ∠ACE=x+y, ∠ BCE = 90-∠ ACE = 90-X-Y. 。
AE = AC,
∴∠ACE=∠AEC=x+y,
BD = BC,
∴∠bdc=∠bcd=∠bce+∠dce=90-x-y+x = 90-y
In △DCE, ∫∠DCE+∠CDE+∠DEC = 180.
∴x+(90 -y)+(x+y)= 180,
X = 45,
∴∠DCE=45。
So the answer is: 45.