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POLYGONS

INDEX

1.-POLYGONS

2.-TYPES OF POLYGONS

REGULAR E IRREGULAR

3.-NAMES OF POLYGONS

4.-TRIANGLES

5.-QUADRILATERALS

6.-REGULAR POLYGONS

7.-STAR POLYGONS

8.-KAMAL ALI

POLYGONS

Polygons are 2-dimensional shapes. They are made of straight lines,

and the shape is "closed" (all the lines connect up).

DEFINITION

Polygon (straight sides)

Not a Polygon (has a curve)

Not a Polygon (open, not closed)

Polygon comes from Greek. Poly- means "many" and -gon means "angle".

Regular and Irregular

If all angles are equal and all sides are equal,

then it is regular, otherwise it is irregular

REGULAR IRREGULAR

Types of Polygons

Name Sides Shape Interior Angle

Triangle (or Trigon) 3 60°

Quadrilateral (or Tetragon) 4 90°

Pentagon 5 108°

Hexagon 6 120°

Heptagon (or Septagon) 7 128.571°

Octagon 8 135°

Nonagon (or Enneagon) 9 140°

Decagon 10 144°

Hendecagon (or Undecagon) 11 147.273°

Dodecagon 12 150°

NAMES OF POLYGONS

Equilateral, Isosceles and Scalene

There are three special names given to triangles that tell how many

sides (or angles) are equal.

There can be 3, 2 or no equal sides/angles:

Equilateral Triangle

Three equal sides Three equal angles

Isosceles Triangle

Two equal sides Two equal angles

Scalene Triangle

No equal sides No equal angles

TYPES OF TRIANGLES

TRIANGLES

A triangle has three sides and three angles. The three angles

always add to 180º

Acute Triangle

All angles are less than 90°

Right Triangle

Has a right angle (90°)

Obtuse Triangle

Has an angle more than 90°

Triangles can also have names that tell you what type of angle is inside:

Properties •Four sides (or edges)

•Four vertices (or corners).

•The interior angles add up to

360 degrees:

Types of Quadrilaterals There are special types of quadrilateral:

QUADRILATERALS

QUADRILATERALS ARE CUADRILATEROS , HERE YOU WILL FIND THE

NAMES IN SPANISH TO COMPARE THEM

The Rectangle

A rectangle is a

four-sided shape

where every angle is

a right angle (90°).

Also opposite

sides are parallel an

d of equal length.

The Rhombus

A rhombus is a four-sided shape where all

sides have equal length.

Also opposite sides are

parallel and opposite angles are equal.

The Square

A square has equal

sides and every angle is

a right angle (90°)

Also opposite sides are

parallel.

A square also fits the

definition of

a rectangle (all angles

are 90°), and

a rhombus (all sides are

equal length).

The Parallelogram

Opposite sides are parallel and equal in length, and

opposite angles are equal (angles "a" are the same,

and angles "b" are the same)

The Trapezoid

(UK: Trapezium)

A trapezoid (called a trapezium in the UK) has

one pair of opposite sides parallel.

It is called an Isosceles trapezoid if the sides

that aren't parallel are equal in length and both

angles coming from a parallel side are equal, as

shown.

Language Note: In the US a "trapezium" is a

quadrilateral with NO parallel sides!

REGULAR POLYGONS

CONSTRUCTIONS

GENERAL METHOD OF CONSTRUCTION OF REGULAR POLYGONS

STAR POLYGONS

CONSTRUCTIONS

SOME EXEMPLES OF

DIFFERENTS

DESIGNS USING STAR

POLYGONS

KAMAL ALI PATTERN