一个正方形和两个等边三角形的位置如图所示,若∠3 = 50°,则∠1 + ∠2 = ( )---**Diagram Description:** The image contains a 3D geometric diagram illustrating points, lines, and vectors. The diagram appears to be composed of two parts: a structure resembling a prism or cuboid, and a set of points with associated coordinate labels and vectors. **Part 1: Prism-like Structure** - Points labeled A, B, C, D forming a base quadrilateral. - Points labeled E, F located above A and B respectively, connected by vertical lines (AE, BF). - Vertical lines extending upwards from C and D are also shown, suggesting a top face exists above C and D (though the points on the top face above C and D are not labeled). - Lines connect A to B, B to C, C to D, and D to A, forming the base quadrilateral. - Lines connect E to F, and potentially connect E to the point above D, and F to the point above C (these lines are dashed or partially visible). **Part 2: Points and Vectors** - Points labeled P, M, N, O. - Lines connecting P to M, P to N, and P to O. These lines have arrows originating from P and pointing towards M, N, and O respectively, representing vectors. - Vector labels $\vec{a}$, $\vec{b}$, $\vec{c}$ are associated with the arrows from P to M, P to N, and P to O respectively. Specifically, $\vec{a}$ is from P to M, $\vec{b}$ is from P to N, and $\vec{c}$ is from P to O. - There are blurry labels near points P, M, N, O which appear to be coordinate values. Based on visual estimation of the blurry text, these coordinates are likely: - P: (1, 1, 1) - M: (-1, 1, 0) - N: (-1, -1, 0) - O: (1, -1, 0) - Another unlabeled arrow is shown originating near point O and pointing generally upwards and to the right. **Overall:** The diagram shows a potential prism and a set of points (P, M, N, O) with defined vectors $\vec{a}, \vec{b}, \vec{c}$ emanating from P, based on their likely coordinates. The relationship between the prism structure and the points P, M, N, O is not explicitly stated or visually clear from the diagram alone, although they might be part of the same 3D space.