△ AOE△ COE in the circle, so AE=CE.

Because ∠AEB=∠DEC.

Two circumferential angles subtended by an arc BD ∠ bad = ∠ BCD.

So △ Abe △ CDE

So AB=CD

Step 2 connect AB and OB

Because de = 1

So be = 1

Angle bde = 45

Angle AOB = 90

So ab = 5 √ 2

Find AO=7 in Rt△AEB.

So AD=7+ 1=8.

Hope to adopt. . .