Class 8 · Chapter 4
Quadrilaterals
Sides, angles, properties of quadrilaterals.
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Ganita Prakash · Class 8 Part 1 (2026-27)
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Tip: NCERT updated the syllabus for 2026-27. The links above open the latest edition on the official portal — chapter titles and numbering may differ from the notes shown here.
Detailed theory
Split quadrilateral into 2 triangles by a diagonal. Each triangle: . Total: .
Key concepts & formulas
01
Quadrilateral has 4 sides, 4 vertices, 4 angles.
02
Sum of interior angles .
03
Types: trapezium (1 pair parallel), parallelogram (both pairs), rhombus (all sides equal), rectangle (all right angles), square (both).
04
Diagonals of parallelogram bisect each other.
05
In rectangle, diagonals are equal; in rhombus, diagonals are perpendicular.