1º DE E.S.O

MATHS
1º DE E.S.O
IES FERNANDO III
CENTRO BILINGÜE
MATHS
UNIT 8: POLYGONS
UNIT 8: POLYGONS
OUTLINE
1 – POLYGONS.
a. ANGLE PROPERTIES OF
TRIANGLES.
b. QUADRILATERALS
c. REGULAR AND IRREGULAR
POLYGONS
d. ANGLE PROPERTIES OF
POLYGONS
2 - VOCABULARY
ASPECTOS LINGÜÍSTICOS
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PRESENT SIMPLE
IMPERATIVE
LOS PASADOS
TO BE
THERE WAS
THERE WERE.
 VERBOS REGULARES/
IRREGULARES EN PASADO
AFIRMATIVA.
 CONTABLES/INCONTABLES
 SOME/ ANY
 GOING TO
 MUST / MUSTN´T
VOCABULARY
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POLYGONS
TRIANGLES
QUADRILATERALS
SQUARE
RHOMBUS
RECTANGLE
PARALLELOGRAM
TRAPEZIUM
PENTAGON
HEXAGON
OCTAGON
DECAGON
PHONETICS
TODOS LOS SONIDOS
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41
MATHS
UNIT 8: POLYGONS
1.- POLYGONS.
A Polygon is a 2-dimensional closed shape with straight sides. In this section, we are going to revise the
properties of polygons.
A. ANGLE PROPERTIES OF TRIANGLES.
The following properties are true for any triangle:
1.- The angles in a triangle add up to 180º.
C
A
B
2.- The exterior angle is equal to the sum of the two opposite interior angles.
B
A
I.E.S. FERNANDO III EL SANTO / PROYECTO BILINGÜE
C
D=A+B
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MATHS
UNIT 8: POLYGONS
B. QUADRILATERALS.
The angles in quadrilaterals add up to 360º. There are special types of quadrilaterals:
 Square: The square is a regular quadrilateral.
o All of its angles are equal (90º).
o All of its sides are of equal length.
o Opposite sides are parallel.
o The diagonals bisect each other at 90º.
o The diagonals are equal in length.
 Rhombus:
o Diagonally opposite angles are equal.
o All of its sides are of equal length.
o Opposite sides are parallel.
o It has two lines of symmetry.
 Rectangle:
o All angles are equal.
o Opposite sides are of equal length.
o Opposite sides are parallel.
o The diagonals are equal in length.
o It has two lines of symmetry.

Parallelogram:
o Diagonally opposite angles are equal.
o Opposite sides are of equal length.
o Opposite sides are parallel.
o It has no lines of symmetry.
 Trapezium:
o One pair of opposite sides is parallel.
o It has no lines of symmetry.
I.E.S. FERNANDO III EL SANTO / PROYECTO BILINGÜE
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MATHS
UNIT 8: POLYGONS
C. REGULAR AND IRREGULAR POLYGONS
The simplest polygon is a triangle ( 3 sides). Polygons can be regular or irregular. A regular polygon has
sides of equal length, and all its interior angles are of equal size.
Irregular polygons can have sides of any length and angles of any size. Here are the names of some
common polygons:
NUMBER OF SIDES
NAME OF POLYGON
3
TRIANGLE
4
QUADRILATERAL
5
PENTAGON
6
HEXAGON
8
OCTAGON
10
DECAGON
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SHAPE
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MATHS
UNIT 8: POLYGONS
D. ANGLE PROPERTIES OF POLYGONS.
The formula for calculating the sum of the interior angles of a regular polygon is:
Where n is the number of sides of the polygon. This formula comes from dividing the polygon up into
triangles using full diagonals. We know that the interior angles of a triangle add up to 180º. For any polygon,
count up how many triangles it can be split into. Then multiply the number of triangles by 180.
NUMBER OF SIDES
SUM OF INTERIOR ANGLES
SHAPE
3
4
5
6
8
10
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A.N.L.: MATHS
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MATHS
UNIT 8: POLYGONS
2.- VOCABULARY
English
Pronunciation
Spanish
Angle
/æŋgəl/
Ängulo
Decagon
/ˈdekagən/
Decágono
Diagonals
/daɪ'ægənəl/
Diagonal
Hexagon
/'heksəgən/
Hexágono
Length
/leŋθ/
Longitud
Octagon
/'ɒktəgən/
Octógono
Parallelogram
/parəleləgram/
Paralelogramo
Pentagon
/'pentəgən/
Pentágono
Polygon
/pəligən/
Polígono
Quadrilateral
/'kwɑ:drə'lætərəl/
Cuadrilátero
Rectangle
/'rektæŋgəl/
Rectángulo
Rhombus
/'rɒmbəs/
Rombo
Sides
/saɪd/
Lado
Square
/skweə(r)/
Cuadrado
Symmetry
/'sɪmətri/
Simetría
Trapezium
/trəpəzɪəm/
Trapecio
Triangle
/'traɪˌæŋgəl/
Triángulo
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