Class 7 · Chapter 9
Geometric Twins (Similarity)
Congruent and similar shapes: what stays the same.
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Ganita Prakash · Class 7 Part 2 (2026-27)
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Detailed theory
Two triangles are congruent if their corresponding sides and angles are equal. Symbol: .
Key concepts & formulas
01
**Congruent**: same shape AND size.
02
**Similar**: same shape, possibly different size.
03
Similar shapes have proportional sides and equal angles.
04
Scale factor = ratio of any pair of corresponding sides.
05
All circles are similar; all squares are similar.