If AB,BC, and CD are equal chords of a circle with O as center, and AD diameter then ∠AOB equals to

If AB,BC, and CD are equal chords of a circle with O as center, and AD

1.	If AB,BC, and CD are equal chords of a circle with O as center, and AD diameter then ∠AOB equals to
Answer» If $A B, B C,$ and $C D$ are equal chords of a circle with $O$ as center, and $A D$ diameter then $∠ A O B$ equals to