Quadrilaterals
General Properties
- Sum of all angles: 360°
- Number of sides: 4
- Number of diagonals: 2
Types & Properties
1. Square
- All sides equal, all angles 90°
- Area: side² or (diagonal²)/2
- Perimeter: 4 × side
- Diagonal: side × √2
- Diagonals bisect each other at 90°
2. Rectangle
- Opposite sides equal, all angles 90°
- Area: length × breadth
- Perimeter: 2(length + breadth)
- Diagonal: √(l² + b²)
- Diagonals bisect each other but not at 90°
3. Parallelogram
- Opposite sides parallel and equal
- Area: base × height
- Perimeter: 2(sum of adjacent sides)
- Opposite angles equal
- Diagonals bisect each other
4. Rhombus
- All sides equal, opposite sides parallel
- Area: (d₁ × d₂)/2 or base × height
- Perimeter: 4 × side
- Diagonals bisect at 90°
- Opposite angles equal
5. Trapezium
- One pair of opposite sides parallel
- Area: ½ × (sum of parallel sides) × height
- Area: ½ × (a + b) × h
6. Kite
- Two pairs of adjacent sides equal
- Area: (d₁ × d₂)/2
Quick Tips
- Square is a special rectangle and rhombus
- Rectangle is a special parallelogram
- Every square is a rectangle but not vice versa