CPCTC- i apparently missed something thing and i don't no how to prove this problem, please help...?

Too many lines here. You need (in addition to the original quadrilateral) only one diagonal; call it AC. This divides the figure into two triangles, which can be shown to be congruent side-angle-side. The remaining sides must then be equal, and the figure is a parallelogram. You work out the details.