Congruent/Similar Triangles (1 Viewer)

[davidbarnes]

We did briefly cover this last year, althoguh I never really grasped the concept at the time (we had several teacher chnages in a short period of time, and they couldn't even control the class, let alone teach).

New year, and a new teacher, and we're back onto congruent and similar triangles. This teacher comes higly reccomended, although I and the rest of the class think he is useless
- He hardly ever explains anything, even when asked
- He has trouble working out the answers to problems (like wtf??)
- He doesn't speak clearly

I've asked him for help, although he hasn't really ghelped much, and tutoring is not an option (remote location), so can anyone advise me on a good website explaining the BASICS/INTERMEDIATES of congruent/simialr triangles, or give a bried explanation?

 

[Ennaybur]

similar triangles have sides in proportion:
a/b =A/B
or all angles are the same

congruent triangles SAS, SSS, AAS, RHS



http://library.thinkquest.org/20991/geo/ctri.html

 

[Ennaybur]

sorry i dont know if that is any help lol

 

[davidbarnes]

Thanks for that link, at a quick glance it looks helpful.

The textbook isn't much use either as it assumes a pre defined understanding.

 

[bos1234]

Congruent Triangles

If two triangles are congruent then ALL their sides and ALL their angles are equal.

To prove two triangles are congruent it is enough to prove that Side Angle Side of one triangle = Side Angle Side of another

Angle Angle Side = AAS of another triangle

Right angle hypotneus side = RHS of another

Side side side = sss of another

And in order to prove the above you need to know such properties like corresponding angles on // lines are equal

co-int. angles = 180 degrees

umm

alternate angles are equal

etc
etc


-----------------
similar triangles

forot.

 

[cuppy]

congruent triangles are exactly IDENTICAL and you use SAS, AAS, SSS, RHS (like everyone has said) to prove that this is so.

similar triangles can be identified by either
(i) all angles equal and/or
(ii) corresponding sides are in the same ratio AND the included angles are equal

 

[watatank]

Why is this in the maths ext thread?

 

[davidbarnes]

I'm confused as to the differernce between congrunet and simialr tringles. In congruent, everything about them (side lengths, angles, etc) are equal, while for 2 triangles to be similar, only the angles of the triangles or the lengths of the sides of the triangles have to be the same?

 

[pLuvia]

Congruent triangles means both triangles are exactly the same, sides, angles etc are all equal

While similar triangles may have the same magnitude of angles, but the sides are different. I.e the sides could be in proportion to one another, and hence the triangles are not exactly the same

Tests for congruency are AAA, SAS, AAS, RHS
Tests for similarity are equiangular, or sides are in the same porportion

 

[davidbarnes]

What is Reflexive Property of Con-gruence?</pre>

 

[pLuvia]

If two triangles were joined together and you were to prove that both of the triangles are congruent, at the line that joins both of the planes together if you reflect both of the triangles about that line, then the non-reflected joint is equal to the reflected joint