Proper reasoning? (1 Viewer)

[zahmad]

Is there proper reasong for Q5bi?
How do they know the second pair is equal.....one pair is 125 degrees,
the other pair you can say is another angles+this angle= 55 degrees (exterior angle triangle)....
you can't say it is 27.5 degrees....it can be 50 and 5 degrees for all we know! (In triangle BDC)

Link:http://www.boredofstudies.org/download.php?id=11042

 

[lyounamu]

Is there proper reasong for Q5bi?
How do they know the second pair is equal.....one pair is 125 degrees,
the other pair you can say is another angles+this angle= 55 degrees (exterior angle triangle)....
you can't say it is 27.5 degrees....it can be 50 and 5 degrees for all we know!

Link:http://www.boredofstudies.org/download.php?id=11042

one is common

and abc = bdc = 125

and the last angle must be equal because the two others are equal.

 

[zahmad]

So you are saying as one is say x, another one is 125, then the other one must be the same? And AAA is not a proof, stupid North Sydney Boys!

 

[Timothy.Siu]

i dont know wat ur talking about but the solution would be

angle ABC = angle BDC
angle C is common

edit damni was beaten

 

[Timothy.Siu]

So you are saying as one is say x, another one is 125, then the other one must be the same? And AAA is not a proof, stupid North Sydney Boys!

yes it is, its similar triangles

 

[lyounamu]

So you are saying as one is say x, another one is 125, then the other one must be the same? And AAA is not a proof, stupid North Sydney Boys!

If the angles are same, they are both equiangular which means that they are similar.

I don't know what's the problem...

 

[zahmad]

Yes, you can say equiangular, but AAA is not a proof! Check your textbook!

 

[lyounamu]

Yes, you can sya equiangular, but AAA is not a proof! Check your textbook!

What are you on about? If they are equiangular, they are similar. It's a basic yr 8 maths, even my yr 7 brother knows that .

You are not proving that they are congruent. READ THE QUESTION.

 

[zahmad]

Yes, everything is right.....except AAA is not a proof that they are similar, as it states in the answer....niether is it a proof for congruent triangles!

 

[lyounamu]

icecream

Having fun being a troll? Please remove yourself from serious discussion.

 

[zahmad]

See previous post

 

[lyounamu]

See previous post

I really don't get what you are saying. In the question, you were supposed to prove that they are similar.

And I said that they are equiangular. And if they ARE equiangular, that means that they are similar. "Equiangular" is a proof.

 

[zahmad]

Can you see the "(AAA)" in the answer....that is incorrect as there is nothing known as AAA....it should state that it is equiangular! Equiangular is the proof...I agree!

 

[Epistemophobia]

Having fun being a troll? Please remove yourself from serious discussion.

no, i'm not.

 

[Graceofgod]

Can you see the "(AAA)" in the answer....that is incorrect as there is nothing known as AAA....it should state that it is equiangular! Equiangular is the proof...I agree!

I have seen answers get full marks like this:

Angle blah = angle blah
Another blah angle = another blah angle
therefore blah triangle is similar to blah triangle (AA)

Even though it is not an OFFICIAL proof, it is clear to the marker what you mean. I would think.

 

[tacogym27101990]

Can you see the "(AAA)" in the answer....that is incorrect as there is nothing known as AAA....it should state that it is equiangular! Equiangular is the proof...I agree!

AAA and equiangular are the same thing idiot

 

[zahmad]

Well thread closed, but AAA is not accpeted, so go ahead and use it if you want....thanks all for clearing it up.

 

[mick135]

one is common

and abc = bdc = 125

and the last angle must be equal because the two others are equal.

probelm i solved

part ii can be solved easier with the sine rule - well i find it easier anyways

 

[Timothy.Siu]

I have seen answers get full marks like this:

Angle blah = angle blah
Another blah angle = another blah angle
therefore blah triangle is similar to blah triangle (AA)

Even though it is not an OFFICIAL proof, it is clear to the marker what you mean. I would think.

why isn't it?

 

[Graceofgod]

why isn't it?

You mean why isn't it an official proof?

When i said that I meant (AA) isn't an official proof, like with congruency and (SAS) etc.