Well according to this diagram, one way to go through these type of problems are that the angles directly opposing the angles in the diagram, are the same angles.
For instance the angle AE and angle FC, are the same they are both equal to 55 degrees. This is also true for the right angle, 90 degrees.
The angle AB and angle G are equal, knowing this information,
Add 55 twice and 90 and x to find the angle from points E to C in clockwise direction.
After finding x, we also know that is the same angle directly opposite to it, D.
