[
  "Use the fact that ABCD is a rectangle (all angles 90°, opposite sides equal).",
  "Since AB = BF and CD = CE, and AB = CD, we know BF = CE. This creates isosceles triangles.",
  "Work through the angles: ∠CBF = 46°, then use triangle angle sums and straight-line angles to find ∠ECD = 136°."
]