RAS question
Find the odd one out: Square, Rectangle, Triangle, Cube, Circle
Correct answer: (C) Cube.
Cube is the odd one out because it is a three-dimensional solid, while square, rectangle, triangle and circle are two-dimensional shapes.
Explanation
The grouping is based on dimensionality. Square, rectangle, triangle and circle are flat, two-dimensional shapes; they can be drawn on a plane. A cube is different because it is a three-dimensional solid. NCERT mathematics material treats shape recognition as involving comparison and sorting of both 2-D and 3-D shapes, and lists common shapes such as square, circle, rectangle, triangle, cubes and cones. Four terms belong to the 2-D group and only cube belongs to the 3-D solid group, so cube is the odd one out.
Why the other options are wrong
- (A) Square is not odd here because it belongs with rectangle, triangle and circle as a two-dimensional shape.
- (B) Triangle is not odd here because it is a two-dimensional shape, matching the main group.
- (D) Circle is not odd here because it is also a two-dimensional shape, unlike the three-dimensional cube.
Concept
Classification by attributes is a core reasoning skill in odd-one-out problems. RAS reasoning often checks whether candidates can identify the governing property instead of relying only on familiar names.