Answer
$\angle ECD=155$
Work Step by Step
$\angle ECD$ and $\angle BCD$ are a linear pair. From exercise 34, we know $m\angle BCD$ is 25 degrees.
Use the definition of a linear pair:
$\angle ECD+\angle BCD=180$
$\angle ECD+25=180$
$\angle ECD+25-25=180-25$
$\angle ECD=155$
