Concept:The Mathematical Variability Principle states that to grasp a mathematical concept, students must experience variations in irrelevant attributes (like size) while the core concept (like rectangle shape) remains constant.
Explanation:The teacher asks students to change length and breadth in different ways.
In (i) and (ii), both dimensions increase or decrease by the same amount, keeping the shape a rectangle.
In (iii), length increases by 1 cm and breadth decreases by 1 cm — the figure may change type (e.g., become a square or general quadrilateral).
By varying the dimensions (irrelevant attributes), students discover that the defining property of a rectangle (equal opposite sides, right angles) stays unchanged only under certain changes.
This systematic variation of irrelevant attributes helps students identify the constant mathematical concept.
Answer:C. Mathematical Variability Principle