请讲解一下这道题的解题思路和知识点---**Extraction Content:** **Question Stem:** 2. 有几个三角形？ **Diagram 1 Description:** * **Type:** Geometric figure. * **Main Elements:** * A large triangle with an apex at the top and a horizontal base at the bottom. * 5 straight lines are drawn from the apex to the base, dividing the base into 6 segments. The entire figure is a triangle divided by lines from the top vertex. **Text below Diagram 1:** 有 ( ) 个三角形 **Diagram 2 Description:** * **Type:** Geometric figure. * **Main Elements:** * A figure resembling a large triangle with an apex at the top and a horizontal base at the bottom, but with an internal horizontal line segment. * 5 straight lines are drawn from the apex towards the base. These lines intersect a horizontal line segment located between the apex and the base, and continue down to the base. * The figure is divided into an upper region (a smaller triangle) and a lower region (a trapezoid) by the internal horizontal line segment. * Both the internal horizontal line segment and the base are divided into segments by the lines from the apex. The internal horizontal line is divided into 6 segments, and the base is divided into 6 segments. **Text below Diagram 2:** 有 ( ) 个三角形