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WISKUNDE

Graad 9

VIERKANTE, PERSPEKTIEFTEKENING, TRANSFORMASIES

Module 21

SOMMIGE VIERHOEKE EN HUL KENMERKE

AKTIWITEIT 1

Om sommige vierhoeke te verken en hul kenmerke te identifiseer

[LU 3.4]

Hier kry jy met sommige baie belangrike vierhoeke te doen. Ons moet hul kenmerke ken, want hulle kom oral om ons voor in die natuur, maar veral in mensgemaakte voorwerpe.

Aangesien jy lynlengtes en hoekgroottes sal moet meet, moet jy seker maak dat jou liniaal en gradeboog byderhand is. Bring ook ‘n skêr saam vir die uitknip van vierhoeke.

Ons begin egter eers met die woord vierhoek. Dit beskryf ‘n plat figuur met vier reguit sye en dus vier hoeke. Ons gaan die sye bestudeer (dikwels in teenoorstaande pare); die binnehoeke (ook dikwels in pare); die diagonale (of hoeklyne), en simmetrie–lyne.

Let op vir nuwe terme en maak seker dat jy hulle goed begryp voordat jy voortgaan.

1. Simmetrie-lyne

Jy is alreeds goed bekend met die vierhoek wat ons ‘n vierkant noem.

Die vierkant

Op die werkvel met vierhoeke is ‘n figuur: “VIERKANT”. Knip dit netjies uit en vou dit om vas te stel of dit enige simmetrie–lyne het.

Simmetrie-lyne is dié lyne waarlangs ‘n mens enige figuur kan vou sodat die twee dele presies opmekaar val.

Maak doodseker dat jy al die simmetrie-lyne gekry het. Teken dan die lyne in op die skets langsaan, met ‘n liniaal. Daar is alreeds een van hulle ingevul as ‘n voorbeeld.

Toevallig is die stippellyn op die skets ook ‘n hoeklyn (diagonaal), aangesien dit van die een hoek na die ander een skuins oorkant getrek is.

- Kyk ‘n bietjie om jou. Kan jy vinnig ‘n vierkant raaksien?

As die vierkant skuins gedruk word, sonder om van grootte te verander, word dit ‘n ruit.

Die ruit

Identifiseer die RUIT op die werkvel. Dit behoort duidelik soos ‘n vierkant wat skuins staan, te lyk. Knip dit uit sodat jy dit kan vou om die simmetrie–lyne op te spoor. Die ruit word ook ‘n rombus genoem.

Weer eens, trek die simmetrie-lyne in op die skets hier langsaan.

- Is die stippellyn in hierdie skets ‘n simmetrie-lyn?

As ons nou die ruit uitrek, word ‘n parallelogram gevorm.

Die parallelogram

Soek die PARALLELOGRAM op die werkvel.

Knip dit uit; vou dit en soek weer die simmetrie-lyne; trek die lyne in op die skets.

- Om iets met ‘n parallelogram-vorm te kry, sal jy lank moet soek. Huiswerk: Kyk of jy iets binne 24 uur kan kry!

Hierdie parallelogram word ‘n reghoek as ons dit regop druk.

Die reghoek

Knip die REGHOEK uit om die simmetrie-lyne te kry om op die sketse in te vul.

- Skryf al die verskille neer wat jy opmerk tussen ‘n reghoek en ‘n vierkant.

As ons nou die twee sykante van die reghoek in verskillende rigtings draai, kry ons ‘n trapesium.

Die trapesium

Die werksvel bevat meer as een TRAPESIUM. (Hier is nog ‘n trapesium langsaan.) Knip hulle uit om die simmetrie-lyne te vind.

- Beskou nou al die soorte trapesiums en skryf ‘n paar sinne om te verduidelik hoe jy hulle sou herken.

Daar is twee soorte VLIEËRS op die werkvel. Knip hulle uit en soek simmetrie-lyne.

Julle weet sekerlik almal wat ‘n vlieër is – die speelding wat aan ‘n toutjie in die lug rondvlieg. Moderne vlieërs het allerhande oulike vorms, maar die vierhoek is vernoem na die eenvoudige papiervlieërs wat maklik gemaak kan word uit twee dun stokkies van verskillende lengtes, papier, gom, ‘n tou, en ‘n stert om dit te stabiliseer.

Questions & Answers

Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Wiskunde graad 9. OpenStax CNX. Sep 14, 2009 Download for free at http://cnx.org/content/col11055/1.1
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