Tell yourself to bypass.

Let the ocy axis intersect with E, then point B (1, 2) oa=bc= 1ab=oc=2.

Let oe=x, ce = 2-x triangle cdeaoe congruence ce=ae and solve X43 by Pythagorean theorem.

D is the vertical line of the X-axis, using the similar triangles proportional relation. The answer should be that I forgot to subtract the abscissa of 1

Well, I don't have plane geometry, which made me think for a while.