SARASAS WITAED NONGKHAEM SCHOOL
BILINGUAL PROGRAMME
2nd SEMESTER
ONLINE
LEARNING
MATHEMATI
for Grade
CS
5
Unit 8
Quadrilaterals
Quadrilaterals
Plane figures or polygons with 4 sides.
The sum of the interior angle of a
quadrilateral is 360˚
Quadrilaterals
All simple closed figures are called POLYGONS.
The smallest number of sides which a polygon can
have is three. This is called TRIANGLE.
A polygon with four sides is called a
QUADRILATERAL.
A four-sided figure has four sides and four inside
angles.
A
B
C
D
ABCD is a four-sided figure
The sides are AB, BC, CD and DA
The angles are ABC, BCD CDA and DAB.
Properties of
Quadrilaterals
Parallelogram
Is a quadrilateral in which both pairs of opposite sides are
parallel and equal.
A
D
B
C
 PARALLEL SIDES (AD II BC and AB II DC)
 EQUAL SIDES (AD = BC and AB = DC)
 EQUAL ANGLES (BAD = BCD and ADC = ABC)
Rectangle
Is a quadrilateral in which the opposite sides are equal and
parallel, and each angle is a right angle.
A
D
B
C
 PARALLEL SIDES ( AD II BC and AB II DC)
 EQUAL SIDES ( AD = BC and AB = DC )
 EQUAL ANGLES ( All angles are equal.)
Rhombus
Is a quadrilateral in which all sides are equal and opposite sides are
parallel. Opposite angles are equal.
A
D
E
PARALLEL SIDES ( AB II CD and BD II AC)
EQUAL SIDES ( AB = BD = DC = CA )
EQUAL ANGLES ( Opposite angles are equal )
B
Square
Is a quadrilateral in which all sides are equal and opposite
sides are parallel, and each ang is a right angle.
A
D
B
C
PARALLEL SIDES ( AD II BC and AB II DC )
EQUAL SIDES ( All the sides are equal)
EQUAL ANGLES ( All the angles are equal)
Kite
Is a quadrilateral in which two pairs of
consecutive sides are equal and none of the
sides are parallel.
D
A
C
B
Trapezoid
Is a quadrilateral in which one pair of opposite
sides is parallel.
A
B
C
D
AB is parallel to CD.
Irregular quadrilateral
All the sides are different lengths.
B
A
C
D
AB ≠ AC ≠ CD ≠ BD
All sides
are equal