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# More maths help because I seem to be an idiot right now watch

1. Ok, so I was trying to do some work to prepare for A levels, but I keep getting the wrong answer to a certain question. I can't work out exactly where I have gone wrong, but I keep getting the answer of 8.01m when the answer sheet says that the answer is 7.52m. Could someone possibly give me a step by step method so that I can see exactly where I keep going wrong?

The question is to find the value of x and this is the diagram: http://tinypic.com/view.php?pic=bi19w7&s=9#.WXjmw73TXqA
2. (Original post by Coco_Monkey)
Ok, so I was trying to do some work to prepare for A levels, but I keep getting the wrong answer to a certain question. I can't work out exactly where I have gone wrong, but I keep getting the answer of 8.01m when the answer sheet says that the answer is 7.52m. Could someone possibly give me a step by step method so that I can see exactly where I keep going wrong?

The question is to find the value of x and this is the diagram: http://tinypic.com/view.php?pic=bi19w7&s=9#.WXjmw73TXqA
HOLD THE FOOK UP, are you doing a level work in the holidays?
3. (Original post by sweet boner)
HOLD THE FOOK UP, are you doing a level work in the holidays?
Yes, one of the sixth forms that I applied to wants us to prepare for a test that there will be on the first week. So I'm doing some stuff in case I end up going there.
4. (Original post by Coco_Monkey)
Yes, one of the sixth forms that I applied to wants us to prepare for a test that there will be on the first week. So I'm doing some stuff in case I end up going there.
Ooooh good luck with the integration, trigonometric equations, Pythagorean identities and all that *******s
you get the idea
5. (Original post by sweet boner)
Ooooh good luck with the integration, trigonometric equations, Pythagorean identities and all that *******s
you get the idea
Can't you help me?! And just looking at the names of those makes me want to cry a little on the inside
6. Can't you just use sine/cosine rule?
Anyway, what do you think you got the maths gcse? I got around 125, is that a 6?
7. (Original post by Coco_Monkey)
Can't you help me?! And just looking at the names of those makes me want to cry a little on the inside
Just by looking at it, i say use pythag to find the hypotenuse.
You know you have 1 right angle and 70 degree angle soo.....
180- (70-90)= You get another angle then it's just easy work.
8. (Original post by Vexillarius)
Can't you just use sine/cosine rule?
Anyway, what do you think you got the maths gcse? I got around 125, is that a 6?
It's in the trigonometry section, so I'm guessing it wants me to use that. And I have no clue about grade boundaries
9. (Original post by Coco_Monkey)
It's in the trigonometry section, so I'm guessing it wants me to use that. And I have no clue about grade boundaries
Btw, sine and cosine rule are both uses of trigonometry AFAIK.
10. (Original post by Vexillarius)
Btw, sine and cosine rule are both uses of trigonometry AFAIK.
I meant the whole sin, cos, tan area because that is the only stuff mentioned in the lesson part of the sheet.
11. (Original post by Coco_Monkey)
It's in the trigonometry section, so I'm guessing it wants me to use that. And I have no clue about grade boundaries
Calculate the hypotenuse (y) of the 60 degree triangle. That is the opposite for the 70 degree triangle.

For the second triangle, you have the opposite (y) and the adjacent (x). Using tan(70) you should be able to calculate x.
12. (Original post by Coco_Monkey)
I meant the whole sin, cos, tan area because that is the only stuff mentioned in the lesson part of the sheet.
In the left/up triangle, you can find the length of its hypotenuse by noting that where you know the adjacent . So you can get . Now that you have the hypoteneuse of the first triangle, you can use where the opposite of 70 degrees is the hypoteneuse of the first triangle (whose length you've found).

You can now use this to rearrange for .
13. (Original post by RogerOxon)
Calculate the hypotenuse (y) of the 60 degree triangle. That is the opposite for the 70 degree triangle.

For the second triangle, you have the opposite (y) and the adjacent (x). Using tan(70) you should be able to calculate x.
cos 60 would be adjacent/hyp, so 11/y, surely?
14. So is the hyp of the first triangle (the diagonal between the two triangles) 22 then? Because that's what I got originally before asking this question.
15. (Original post by AnIndianGuy)
Yes Roger got it wrong.

You could use sin 30 too obvs
Oops. Yes.
16. (Original post by rogeroxon)
oops. Yes.
roger help me
17. (Original post by Coco_Monkey)
So is the hyp of the first triangle (the diagonal between the two triangles) 22 then? Because that's what I got originally before asking this question.
yes
18. (Original post by Coco_Monkey)
roger help me
The diagonal is y:

Substitute for cos(60) to simplify y.

Rearrange and you'll get the answer.
19. (Original post by Zacken)
yes
Then how does x = 7.52? Have I used the wrong ratio to find the answer? I used Tan.
20. (Original post by Coco_Monkey)
Then how does x = 7.52? Have I used the wrong ratio to find the answer? I used Tan.
how did you use tan

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