△ 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. . .