如图BD=DC,∠BDA=45°,∠B=3∠C,怎么求∠C的度数---**Chart/Diagram Description:** * **Type:** Geometric figure, specifically a triangle with a line segment from a vertex to a point on the opposite side. * **Main Elements:** * **Points:** Points A, B, D, C are labeled. * **Lines:** Line segments AB, BC, AC, and AD are depicted. * **Connections:** * Point A is connected to points B, D, and C by line segments AB, AD, and AC respectively. * Points B, D, and C are on the same horizontal line segment, forming the side BC. * Point D is located on the line segment BC, between B and C. * **Relative Position and Direction:** Point A is located above the line segment BC. Points B, D, and C are collinear and arranged from left to right in that order on the horizontal line.