1. The problem is to categorize triangles based on their angle types: acute, obtuse, or right. 2. Definitions: - An acute triangle has all angles less than 90 degrees. - An obtuse triangle has one angle greater than 90 degrees. - A right triangle has one angle exactly 90 degrees. 3. Given the shapes: - Triangles with a right-angle marker belong to the "Triangles with one right angle" category. - Triangles with an obtuse angle (marked > 90°) belong to the "Triangles with an obtuse angle" category. - Triangles with all angles acute (no right or obtuse markers) belong to the "Triangles with all acute angles" category. 4. Therefore, the correct categorization is: - Triangles with all acute angles: triangles without right or obtuse markers (top-right and bottom-center positions). - Triangles with an obtuse angle: triangles with one angle > 90° (center and bottom-left positions). - Triangles with one right angle: triangles with a right-angle marker (top-left and top-center positions). This classification follows the angle properties of triangles and helps in understanding their types clearly.