请解答图片中的题，并给予提示---**Textual Information:** 如图, 已知直线 l 与 ⊙O 相离, OA ⊥ l 于点 A, 交 ⊙O 于点 P, OA=5, AB 与 ⊙O 相切于点 B, BP 的延长线交直线 l 于点 C. (1) 求证: AB = AC; (2) 若 PC = 2√5, 求 ⊙O 的半径. **Chart/Diagram Description:** * **Type:** Geometric diagram. * **Main Elements:** * A circle with center O. * A horizontal line labeled 'l'. * A point A on line 'l'. * A vertical line segment OA connecting the center O to point A. OA is perpendicular to line 'l' at A. * The line segment OA intersects the circle ⊙O at point P (P is between O and A). * A point B on the circle ⊙O. * A line segment AB which is tangent to the circle ⊙O at point B. * A line passing through points B and P, extended to intersect line 'l' at point C. * Labels: O (center of the circle), P (intersection of OA and the circle), A (foot of perpendicular from O to l, and on line l), B (tangency point on the circle), C (intersection of line BP and line l). * Angles: A right angle is indicated at point A, formed by OA and line l. * Lines: OA is perpendicular to l. AB is tangent to the circle at B. BP is a line segment extended to C. * Relative Positions: Circle ⊙O is above line l. O, P, A are collinear, with P between O and A. A, C are on line l, with C to the left of A. B is on the circle. AB is a line segment. Line BP passes through P and B, and intersects line l at C.