URGENT HELP!! LINKS WILL BE REPORTED

Here is their argument. given the obtuse angle x, we make a quadrilateral abcd with ∠dab = x, and ∠abc = 90◦, and ad = bc. say the perpendicular bisector to dc meets the perpendicular bisector to ab at p. then pa = pb and pc = pd. so the triangles pad and pbc have equal sides and are congruent. thus ∠pad = ∠pbc. but pab is isosceles, hence ∠pab = ∠pba. subtracting, gives x = ∠pad−∠pab = ∠pbc −∠pba = 90◦. this is a preposterous conclusion – just where is the mistake in the "proof" and why does the argument break down there?

In a right triangle δabc, the length of leg ac = 5 ft and the hypotenuse ab = 13 ft. find: b the length of the angle bisector of angle ∠a.

Atransformation was performed on rectangle c as shown in the graph. what type of transformation was performed? does that transformation result in congruent shapes? you people