We know ∠FED is 66°, and ∠FED & ∠DEB (or z) equal 90° degrees. That means ∠z is 24° degrees as is ∠x, since it is adjacent to ∠z. ∠x and ∠y are supplementary, which meant they equal 180°. Subtract 24° (∠x's measurement ) from 180° to get your final answer of y being 156°.
