详细讲解上题，着重拓展到适用该类题。---**Question 23:** * **Question Stem:** 23. (10 分) 如图, 已知 AD 是△ABC 的中线, AE 是△ABD 的中线, AB = DC, 求证: AC = 2AE. * **Translated Question Stem:** 23. (10 points) As shown in the figure, given that AD is the median of △ABC, AE is the median of △ABD, AB = DC, prove that AC = 2AE. * **Other Relevant Text:** * 23 题图 (Figure for Question 23) * **Chart/Diagram Description:** * **Type:** Geometric figure, specifically a triangle with interior line segments. * **Main Elements:** * **Points:** Five labeled points: A, B, C, D, E. * **Lines/Segments:** * A large triangle △ABC is depicted. * Point D lies on the side BC, and segment AD connects vertex A to D. * Point E lies on the segment BD, and segment AE connects vertex A to E. * Segments AB, AC, BC, AD, and AE are visible. * **Relative Position:** * Points C, D, E, B are collinear, arranged horizontally from left to right in the order C, D, E, B. * Point A is positioned above the line segment CB. * Segments AD and AE originate from vertex A and terminate on the line segment CB. * **Labels and Annotations:** All vertices and points (A, B, C, D, E) are clearly labeled. The annotation "23 题图" (Figure for Question 23) is placed above the diagram.