Using only elementary geometry, determine angle x. Provide a step-by-step proof.
You may only use elementary geometry, such as the fact that the angles of a triangle add up to 180 degrees and the basic congruent triangle rules (side-angle-side, etc.). You may not use more advanced trigonomery, such as the law of sines, the law of cosines, etc.
Small hints are available on the site, but they’re very small. Think of this as something to keep you busy while you’re digesting all that turkey.
(The first Paltry Geometric Dilemma.)