1. The problem asks which of the given shapes are always similar. 2. Let's recall the definitions: - Triangles: All triangles with the same angles are similar, but not all triangles are similar. - Rectangles: All rectangles have four right angles, but their side lengths can vary, so they are not necessarily similar. - Parallelograms: They have opposite sides parallel, but angles and side lengths can vary, so not all are similar. - Squares: All squares have equal sides and all right angles, so all squares are similar. 3. Therefore, the only shape that is always similar to any other of its kind is the square. 4. The answer is (d) squares. 5. The interval notations shown ([2 ˜ 5), ]2 ˜ 5], [2 ˜ 5], ∅ = [2 ˜ 5]) represent different types of numeric intervals but are unrelated to the similarity of shapes. Final answer: (d) squares