Math Is Fun Forum

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Similar Triangles

Hello mathematicians.
I'm back: D
I wanted to know if they know how to make similar triangles without drawing parallels to the sides of the triangle.

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

Bob

Administrator

Registered: 2010-06-20

Posts: 10,627

Re: Similar Triangles

hi mathmatiKs

To be similar, the angles must be the same or one triangle must be an exact enlargement of the other.

The parallel lines method works because it maintains the same angles.

You could try extending each side and doubling the lengths. (or substitute any other scale factor, eg trebling)

You could draw a line perpendicular to each side.  The triangle these make would also be similar. (diagram below)

You could extend this idea to making the three new lines at any fixed angle to the original sides.

I could go on .........

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

Thanks Bob Bundy
Asked because I found a method to draw three triangles similar to an extent that they have a special relationship within the interior angles of the first triangle.
How sould upload a picture to show you an example?

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

Bob

Administrator

Registered: 2010-06-20

Posts: 10,627

Re: Similar Triangles

hi mathmatiKs

I'm assuming you have the picture on your computer.

(1) make sure you click Post Reply not Quick reply

Your picture should not be too large ( < 100Kb)

(2) Click Image Upload

(3) and browse to your picture

(4) click submit.

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

This is what I was saying.

....  500 kb

yeahh

I do not see the picture I uploaded.

Last edited by mathmatiKs (2012-07-09 16:53:15)

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

Bob

Administrator

Registered: 2010-06-20

Posts: 10,627

Re: Similar Triangles

hi mathmatiKs

500 Kb is too large.  If you try to upload it doesn't appear.  That happened to me for the shot in post 4.

I'm using Windows 7 so I used Paint to reduce it in size.  That's why the shot is poor resolution.

For diagrams I use GIF format.  That takes a lot less space than the same in JPG.

Or maybe you can store it on-line somewhere and point to it using

[img]web address of picture[/img]

If all else fails you could write a written description such as:

Draw a line AB.  At A,  mark a 30 degree angle and draw the line AC so that CAB = 30.  Drop a perpendicular from C to B. etc etc.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Similar Triangles

Hi mathmatiKs

You can store the pics on mediafire then link to there from here.

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“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

Hi Bob bundy.
I was down to 100kb but nothing happened.

Thanks anonimnystefy

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

Hi Bob Bundy
Tell the process to draw the triangles would be very long, since it does not write well in English (I'm using a little tradutor)

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

Hello mathematicians.
I found an easier way of construction of similar triangles.
I'm still seeing in relation to the building or if the relationship is either.

Here's the procedure:
1) Draw the triangle ABC.
2) Taking the measure of segment AB and draw a circle in C
3) Taking the measure of segment BC and draw a circle at
4) Taking the measure of segento CA and draw a circle in B
5) After this, you are 3 circles with 9 points of intersection. Joining of three points, the right way, you are 3 similar triangles.

Oh, and something else. I have to prove but I can use what I had found earlier for construction of similar triangles. For now I let them try and see how fun and crazy it is drawing similar triangles using ruler, pencil and compass.

I hope they serve to help or interest to them.
(Excuse me for mistakes but I use a translator )

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Similar Triangles

Hi mathmatiKs;

Sounds like geogebra is what you need.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

Hi Bobbym.

I am currently using Kig, which in my opinion is better.
Try it.

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

Testing ...
Do I have to wait to upload an image that is completely or just subis you can post?

Last edited by mathmatiKs (2012-08-04 08:20:46)

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Similar Triangles

I am getting for the drawing:

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

(((The triangles are similar:  ENG   NFM   GMH ))) no valid
Ups!
The construction is not correct!

Last edited by mathmatiKs (2012-08-04 08:27:07)

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

Measure the segment AB and draw a circle at center C
Measure the AC segment and draw a circle in center B
Measure the segment CB and draw a circle in center A

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Similar Triangles

Testing ...
Do I have to wait to upload an image that is completely or just subis you can post?

Use the Upload Slots.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

hi mathmatiKs

I'm assuming you have the picture on your computer.

(1) make sure you click Post Reply not Quick reply

Your picture should not be too large ( < 100Kb)

(2) Click Image Upload

(3) and browse to your picture

(4) click submit.

I use this.

What browser do I have to use?
Firefox Mozzilla
Google Chrome
Etc..

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Similar Triangles

I use Firefox.

This is my new drawing I do not think it is correct.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

This well done. I could put names to the points?

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Similar Triangles

Okay, I will label the points now. They are slightly out of position because I did them manually.

How are you coming with your upload?

Why are you not using 2 intersecting lines to create as many similar triangles as you need?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

mathmatiKs

Member

Registered: 2012-04-14

Posts: 45

Re: Similar Triangles

Wait for me a little hard to see more or less.
Since I have not yet found an easy way to pull it.
Waiting For

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"... And as we let our own light shine, we unconsciously give other people permission to do the same. As we're liberated from our own fear, our presence automatically liberates others."

Bob

Administrator

Registered: 2010-06-20

Posts: 10,627

Re: Similar Triangles

hi mathmatiKs

I have drawn triangle ABC.

Measured AB and made circle centre C with radius CD so that CD = AB

Measured AC and made circle centre B with radius BE so that BE = AC

Measured BC and made circle centre A with radius AF so that AF = BC (slightly inaccurate as the point is hard to place exactly)

This gives first diagram.  The circles only cross in 6 points.

I made any three circles for my second diagram and there are always a maximum of 6 points!

???

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Similar Triangles

Hi;

Can you see my drawing?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,627

Re: Similar Triangles

Yes.  You also have 6 points.  (I typed 8 points in error but have edited it.  I have trouble counting to 8 !!    )

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob