首先要指出这个是什么类的题型，用到的是什么知识点，并解释相关的基本的解题思路和知识点。然后通过图文并茂的方式来讲解这个题目。最后在进行整体的总结---**Extracted Content:** **Question Stem:** 如图, 四边形 ABCD 与 BDEF 均为菱形, FA=FC, 且 ∠DAB = ∠DBF = 60° **Sub-questions:** (1) 求证: AC ⊥ 平面 BDEF; (2) 若菱形 BDEF 边长为 2, 求三棱锥 E-BCD 的体积. **Chart/Diagram Description:** * **Type:** 3D geometric figure illustrating a spatial arrangement of points and lines. * **Main Elements:** * **Points:** Labeled points are A, B, C, D, E, F. * **Lines:** * Solid lines connect points A-B, B-C, C-D, A-D, B-D, B-E, B-F, D-E, D-F, E-F, A-F, F-C. * Dashed lines connect points A-C, B-E, D-F, A-D, C-D, A-B, B-C. (Note: The dashed lines represent hidden edges or diagonals. Specifically, AC, BE, and DF appear as diagonals of rhombuses/related figures. AD, DC, AB, BC are edges, but rendered as dashed in the base, suggesting the base plane ABCD is viewed from above). * **Shapes:** The figure shows two rhombuses, ABCD and BDEF, sharing the edge BD. Points A, B, C, D appear to form a base plane (possibly non-horizontal) with ABCD being a rhombus. Points B, D, E, F form another rhombus BDEF. Point E and F are positioned above the base. * **Labels and Annotations:** Points are labeled A, B, C, D, E, F. * **Relative Position and Direction:** ABCD is described as a quadrilateral and a rhombus, suggesting it lies in a plane. BDEF is described as a rhombus, sharing the edge BD with ABCD. Point A is connected to F and F to C. *(Note: The rendering of lines as solid or dashed seems inconsistent with standard hidden line conventions for all parts of the figure, particularly in the base ABCD.)*