Multi choice geometry question Watch

REASON_Lighters
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#1
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Help please.

I like an idiot when for C// 8 which is ofc wrong.

I know it involves the area of the triangle but I don't know exactly how to link it to this question

This is the link, https://twitter.com/natekeegan1986/s...29348435136512

Thanks all, csa' ><
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ghostwalker
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#2
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#2
(Original post by REASON_Lighters)
Help please.

I like an idiot when for C// 8 which is ofc wrong.

I know it involves the area of the triangle but I don't know exactly how to link it to this question

This is the link, https://twitter.com/natekeegan1986/s...29348435136512

Thanks all, csa' ><
Area of triangle = 1/2 x base x perpendicular height.

See if you can find two ways of working it out, one of which will include your unknown, BE.
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REASON_Lighters
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(Original post by ghostwalker)
Area of triangle = 1/2 x base x perpendicular height.

See if you can find two ways of working it out, one of which will include your unknown, BE.
I can see how it would be that and how I would get it from that but I'm still stuck.

Can you tell me which triangles to use, to do this, ie is it ADC and BEC or the others
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TenOfThem
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(Original post by REASON_Lighters)
I can see how it would be that and how I would get it from that but I'm still stuck.

Can you tell me which triangles to use, to do this, ie is it ADC and BEC or the others
You just use the big triangle ABC

1/2 base x height

Use 2 different sides as the base - the area will not change
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REASON_Lighters
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(Original post by TenOfThem)
You just use the big triangle ABC

1/2 base x height

Use 2 different sides as the base - the area will not change
So irs 0.5*12*x=0.5*10*x ? :confused:
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TenOfThem
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(Original post by REASON_Lighters)
So irs 0.5*12*x=0.5*10*x ? :confused:
NO

what is x in your equation there
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REASON_Lighters
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It doesnt work because none of the values fit in...
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REASON_Lighters
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#8
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(Original post by TenOfThem)
NO

what is x in your equation there
ABC area = 0.5*12*Perpendicular height OR 0.5*10* Perpendicular height
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TenOfThem
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(Original post by REASON_Lighters)
ABC area = 0.5*12*Perpendicular height OR 0.5*10* Perpendicular height
yes

I still don't know what x was meant to be

Is it the perpendicular height when 12 is your base or is it the perpendicular height when 10 is the base

Clearly these perpendicular heights are not the same - you could see that because your equation was nonsense

Look at your diagram - you have one of these perpendicular heights
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REASON_Lighters
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#10
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(Original post by TenOfThem)
yes

I still don't know what x was meant to be

Is it the perpendicular height when 12 is your base or is it the perpendicular height when 10 is the base

Clearly these perpendicular heights are not the same - you could see that because your equation was nonsense

Look at your diagram - you have one of these perpendicular heights
Thanks for the help:

I turned my book around lol and figured what you were talking about.
0.5*10*AD=0.5*AC*BE

Therefore since AD = 9.
.5*10*9=45

So 0.5*AC*BE=45

Then 0.5*12*BE=45

So 6x=45

Therefore x=7.5

Wow tricky question but yeah thats right, thanks for your help xD
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REASON_Lighters
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(Original post by TenOfThem)
yes

I still don't know what x was meant to be

Is it the perpendicular height when 12 is your base or is it the perpendicular height when 10 is the base

Clearly these perpendicular heights are not the same - you could see that because your equation was nonsense

Look at your diagram - you have one of these perpendicular heights
So the area of two triangles within a triangle is the same. Does that mean that the overall area of the big triangle is the same or not?
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REASON_Lighters
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(Original post by TenOfThem)
yes

I still don't know what x was meant to be

Is it the perpendicular height when 12 is your base or is it the perpendicular height when 10 is the base

Clearly these perpendicular heights are not the same - you could see that because your equation was nonsense

Look at your diagram - you have one of these perpendicular heights
How come you cant do pythagoras of BEC so sqrt 10^2-6^2=9

I know thats the wrong answer but how come it couldnt be that...

Thanks again
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TenOfThem
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(Original post by REASON_Lighters)
Thanks for the help:

I turned my book around lol and figured what you were talking about.
0.5*10*AD=0.5*AC*BE

Therefore since AD = 9.
.5*10*9=45

So 0.5*AC*BE=45

Then 0.5*12*BE=45

So 6x=45

Therefore x=7.5
Yes
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TenOfThem
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(Original post by REASON_Lighters)
So the area of two triangles within a triangle is the same. Does that mean that the overall area of the big triangle is the same or not?
I do not know what you are asking here
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TenOfThem
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#15
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(Original post by REASON_Lighters)
How come you cant do pythagoras of BEC so sqrt 10^2-6^2=9

I know thats the wrong answer but how come it couldnt be that...

Thanks again
What makes you think that E is in the middle of AC
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REASON_Lighters
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#16
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(Original post by TenOfThem)
What makes you think that E is in the middle of AC
I thought abc was an equilateral triangle so e had to be the midpoint.
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TenOfThem
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(Original post by REASON_Lighters)
I thought abc was an equilateral triangle so e had to be the midpoint.
You thought it was equilateral even though you were told that AC=12 and BC=10
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REASON_Lighters
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#18
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#18
(Original post by TenOfThem)
I do not know what you are asking here
So a triangle can only have one area then
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TenOfThem
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#19
(Original post by REASON_Lighters)
So a triangle can only have one area then
Is that a serious question
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REASON_Lighters
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#20
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(Original post by TenOfThem)
You thought it was equilateral even though you were told that AC=12 and BC=10
You make it sound so easy, yes in retrospect I see now. Thank you :<)
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