GCSE Maths Question

ElRazur · 2 Jun 2006 at 21:52

ballistic said:
find me the 90 degree angle then..

I think (i am rubbish at maths) you have to split it from C so as to get the angle and go on from there. :confused:

Conrad11 · 2 Jun 2006 at 21:52

Conrad11 said:
CE =

(9/6) * 8 = 12cm (I think)

BC =

(6/9) * 13.5 = 9cm

Rich1988 · 2 Jun 2006 at 21:53

kip02 said:
I don't know if it has anything to do with it, but just had a look in one of my gcse maths books that i still have lying around 2 years later and it has a help guide at the top of one of the pages. Don't know if it is the same thing as i wasn't too good at maths.

thats what I first thought, alas pythagoras' theorem is for triangles with 90 degree corners only.

ballistic · 2 Jun 2006 at 21:53

1) THERE IS NO HYPOTENUSE - we don't know any angle is 90 degrees
2) This is NOT an equilateral triangle - the lengths are different

again: you get the answer using ratios

ElRazur · 2 Jun 2006 at 21:54

Oh i see, Shame on you lot, cant even sort a gcse question...

Smithy · 2 Jun 2006 at 21:56

ooh i like these

ok, because the lines AB and DE are parallel, its satisfactory to say that the two triangles are 'similar'. Meaning one is a ratio of the other.

deviding any one side by its respective similar side on the other triangle gives us this ratio.

9/6 = 1.5. So ratio is 1.5.

8x1.5 = 12, CE = 12.

13.5 / 1.5 = 9, BC = 9.

Violent-J · 2 Jun 2006 at 21:59

It's a trigonometry question, I only done my GCSE maths this time last year and got a b, but i forgot it all already lol.

It's to do with Syn, Cos, Tan or SOH CAH TOA as my teacher used to say.

syn is opposite over hypotenuse

cos is adjacent over hypotenuse

tan is opposite over adjacent

Something like that...

Nix · 2 Jun 2006 at 21:59

I used to be quite good at maths, I've forgot all this now

ballistic · 2 Jun 2006 at 22:00

Violent-J said:
It's to do with Syn, Cos, Tan or SOH CAH TOA as my teacher used to say.

syn is opposite over hypotenuse

cos is adjacent over hypotenuse

tan is opposite over adjacent

hmm good luck with that..

Conrad11 · 2 Jun 2006 at 22:00

Violent-J said:
It's a trigonometry question, I only done my GCSE maths this time last year and got a b, but i forgot it all already lol.

It's to do with Syn, Cos, Tan or SOH CAH TOA as my teacher used to say.

syn is opposite over hypotenuse

cos is adjacent over hypotenuse

tan is opposite over adjacent

Something like that...

it is NOT triganometry....or triganometry is not the desired method that the examiners what the students to be working it out with and therefore they would only get 1 mark for the right answer and not the working out.

The examiners want you to work it out using the method i stated earlier

ichabod crane · 2 Jun 2006 at 22:01

the answer is the numbers mirrored, the two lines are parralel so therefore BC= 8, CE= 13.5

Smithy · 2 Jun 2006 at 22:04

ichabod crane said:
the answer is the numbers mirrored, the two lines are parralel so therefore BC= 8, CE= 13.5

thats completely incorrect, it isnt an equilateral triangle.

ichabod crane · 2 Jun 2006 at 22:05

just realised its ratios.

ElRazur · 2 Jun 2006 at 22:06

This thread is crazy, we actually spend more time debating than helping the little girl by answering the question....

I dont care if it is hypotenouse, hypotension, soccer team or equalliser angle, .....

lay-z-boy · 2 Jun 2006 at 22:07

mine is on monday, proper worrying over things like this.

crunchman · 2 Jun 2006 at 22:10

lay-z-boy said:
mine is on monday, proper worrying over things like this.

Mine's on Monday too.

SimonTW · 2 Jun 2006 at 22:20

Yup, Monday too. Although I have Geography in the morning, which I'm more worried about because there is more to revise for Geography than Maths.

And yer, that question is a simple ratio question. As people have said, you have the lengths for two sides that are similar, so divide the bigger number by the smaller one, and that is the ratio. Then divide/multiply the other sides to reach your answer. Simple.

Nix · 2 Jun 2006 at 22:23

SimonTW said:
Yup, Monday too. Although I have Geography in the morning, which I'm more worried about because there is more to revise for Geography than Maths.

And yer, that question is a simple ratio question. As people have said, you have the lengths for two sides that are similar, so divide the bigger number by the smaller one, and that is the ratio. Then divide/multiply the other sides to reach your answer. Simple.

If you want to know anything about Geography, I should be able to help.

georges · 2 Jun 2006 at 23:06

I got it too simonTW

Go the same next monday too.. Geog + Maths on the same day on two mondays is a bad combo imo..

If you want to explain it to her:

The two angles on the crossing (ACB and DCE) are the same as angles opposite on a two line intersection are identical..

Because of this, with the two lines AB and DE parallel, they must just be scaled up, as if you think about it, it's just like moving DE further down down and lengthening it, so you must lengthen them by the same ratio.

Hard to explain without pointing at stuff on the diagram though.

Abyss · 2 Jun 2006 at 23:13

Smithy said:
ooh i like these

ok, because the lines AB and DE are parallel, its satisfactory to say that the two triangles are 'similar'. Meaning one is a ratio of the other.

deviding any one side by its respective similar side on the other triangle gives us this ratio.

9/6 = 1.5. So ratio is 1.5.

8x1.5 = 12, CE = 12.

13.5 / 1.5 = 9, BC = 9.

Quoted as its one of the very few posts here that is correct! lol.

You will probably get one mark for working out the ratio (1.5), and a mark for both i) and ii)