QUADRILATERALS

A quadrilateral is a polygon with FOUR sides. Q

S

R

P

It is named by its VERTICES in a clockwise position.

*The figure above is named PQRS, QRSP, RSPQ, or SPQR .

2

31

4

REMEMBER :The order of the vertices is important !

TERMS :

DC

B

AIn quadrilateral ABCD, the vertices are A, B, C and D.

Vertices A and B, B and C, C and D, D and A are consecutive vertices.

Vertices A and C, B and D, are opposite vertices.

A B

D C

Two sides with a common vertex, like AB and BC, are consecutive sides.

AB, and DC, AD and BC, on the other hand are opposite sides.

`

D

BA

C

Two angles with a common side, like <A and <D, are consecutive angles.

<A and <C, <B and <D, on the other hand are opposite angles.

A

B

C

D Segments joining opposite vertices like AC and BD are called diagonals of the quadrilateral.

KINDS of QUADRILATERALS :M

N

O

PQ

R S

T

CONVEXNONCONVEX

Diagonals of quadrilateral intersect.

Diagonals of quadrilateral do not intersect

TYPES of QUADRILATERALS :

TrapezoidParallelogram

Rectangle Rhombus

Square

Quadrilateral

TRAPEZOID

A trapezoid is a quadrilateral with exactly a pair of parallel sides.

base angles

base

base

legleg

*If the legs are congruent , trapezoid is an isosceles.

*If a quadrilateral has no parallel sides, it is called a trapezium.

PARALLELOGRAM

A parallelogram is a quadrilateral with two pairs of congruent and parallel sides.

RECTANGLE

A rectangle is a parallelogram with four right angles.

RHOMBUS

A rhombus is a parallelogram with four congruent sides.

SQUARE

A square is a parallelogram with four congruent sides and four congruent angles.

Parallelogram

RhombusRectangle

Square

REMEMBER !

always alway

s

always always

sometimes

sometimessometimes

sometim

es

THANK YOU !

MARIVIC M. MARQUINEZII – B BSE Mathematics