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Four Sided Figures - Quadrilaterals

• Quadrilaterals

Quadrilaterals are 2-dimensional closed shapes with four straight sides in which the 4 angles add up to 360°.

• Types of Quadrilaterals

Quadrilaterals are divided into two groups: (1) parallelograms and, (2) other quadrilaterals.

quadrilaterals

• Properties of Quadrilaterals

square

• All four sides are equal
• Opposite sides are parallel to each other
• All four angles are equal to 90°
• Diagonals are equal and bisect each other at 90°
• Interior angles add up to 180°
• Each diagonal bisects two opposite interior angles

rhombus

• All four sides are equal
• Opposite sides are parallel to each other
• Opposite angles are equal
• Diagonals bisect each other at 90°
• Interior angles add up to 180°
• Each diagonal bisects two opposite interior angles

rectangle

• Opposite sides are equal
• Opposite sides are parallel to each other
• All four angles are equal to 90°
• Diagonals are equal and bisect each other
• Interior angles add up to 180°

parallelogram

• Opposite sides are equal
• Opposite sides are parallel to each other
• Opposite angles are equal
• Interior angles add up to 180°

Trapezium

• One pair of opposite sides are parallel to each other
• Interior angles between the parallel lines add up to 180°
• ∠a + ∠d = 180° and
∠b + ∠c = 180°

isosceles trapezium

This property only apply to Isosceles Trapezium

• The sides that aren't parallel are equal in length
• There are two sets of equal angles
• ∠a = ∠b & ∠d = ∠c

kite

• Two sets of equal adjacent sides
• Angles are equal where the adjacent sides meet
• Diagonal intersect each other at 90°
• One of the diagonal bisect the other

• Regular quadrilaterals

The only regular quadrilateral is square that has four equal sides and four equal angles. Rest of the quadrilaterals are irregular quadrilaterals.