1. In ⊙ O, the length of the chord AB is 8㎝ the distance from the center of the circle to AB is 3㎝ Find the radius of ⊙ o.
2. In ⊙O, AB AC is two perpendicular and equal chords, OD⊥AB is in D, OE⊥AC is in E, and quadrilateral ABOE is square.