You are Here: Home

IGCSE Question help Tweet

Maths and statistics discussion, revision, exam and homework help.

Announcements Posted on
1. IGCSE Question help
I've tried so many approaches to this that any help would be really be appreciated:

Semi circular bridge with 6m inner walls, a 6m road running through the middle and a radius of 7.16m. What is the tallest load that a 3m wide flat bed truck could pass through in the middle of the road. I've tried 3Tan45 and various other combinations and got nowhere!

Hope someone can help!
2. Re: IGCSE Question help
(Original post by Arcane Barn Elk)
I've tried so many approaches to this that any help would be really be appreciated:

Semi circular bridge with 6m inner walls, a 6m road running through the middle and a radius of 7.16m. What is the tallest load that a 3m wide flat bed truck could pass through in the middle of the road. I've tried 3Tan45 and various other combinations and got nowhere!

Hope someone can help!
Is there a picture that comes with this question? Or can you say which textbook/exam this is from?
3. Re: IGCSE Question help

I'm also stuck on this one too. (click on image for larger view). I have to find x, y and z. x and z intersect on the circumference.
Thanks for any help! I got as far as x =6?
4. Re: IGCSE Question help
(Original post by Arcane Barn Elk)

I'm also stuck on this one too. (click on image for larger view). I have to find x, y and z. x and z intersect on the circumference.
Thanks for any help! I got as far as x =6?
Your picture is very confusing. I don't know exactly what x, y and z represent and am not sure which triangle you are talking about.

Where did you get these questions from?
Last edited by notnek; 07-08-2012 at 08:30.
5. Re: IGCSE Question help
(Original post by notnek)
Is there a picture that comes with this question? Or can you say which textbook/exam this is from?
This is the diagram that is in the materials (its a distance learning course):

6. Re: IGCSE Question help
(Original post by Arcane Barn Elk)
This is the diagram that is in the materials (its a distance learning course):

That's the diagram that you were given? Looks more like a drawing on MSPaint.

Shouldn't it be a 3d diagram? Which part of the inner walls are 3m? Where does the road start/finish?

Can you post everything that the question comes with?
Last edited by notnek; 07-08-2012 at 08:37.
7. Re: IGCSE Question help
(Original post by notnek)
Your picture is very confusing. I don't know exactly what x, y and z represent and am not sure which triangle you are talking about.

Where did you get these questions from?
Sorry I'm rubbish with Paint!

X, Y and Z are chords and tangents. Y is the tangent across the top of the smaller circle. Z is the chord running across the same circle. X is the chord that crosses the overlap between the larger and smaller circle.

The triangle is the small one formed by the tangent across the larger and smaller circles and the chords Z and X. The length given for the part of the chord before X is 2, and that before the chord labelled Z is 5. The length given for the tangent before that labelled Y is 4.

I agree it is confusing. The questions are from a distance learning course that I am doing but are past paper ques apparently.
Last edited by Arcane Barn Elk; 07-08-2012 at 08:38.
8. Re: IGCSE Question help
Can't you take a picture of your materials and post them here?
9. Re: IGCSE Question help
(Original post by notnek)
That's the diagram that you were given? Looks more like a drawing on MSPaint.

Shouldn't it be a 3d diagram? Which part of the inner walls are 3m? Where does the road start/finish?

Can you post everything that the question comes with?
It is my drawing on MSPaint! But has the same info as that question itself. The road in the middle (unshaded) is 6m wide. The height of the inner walls is 6m. The radius (of the whole circle) is 7.16m. I have to find the maximum height of the truck that can pass in the centre of the road when the truck is 3m wide.

10. Re: IGCSE Question help
(Original post by Arcane Barn Elk)
Sorry I'm rubbish with Paint!

X, Y and Z are chords and tangents. Y is the tangent across the top of the smaller circle. Z is the chord running across the same circle. X is the chord that crosses the overlap between the larger and smaller circle.

The triangle is the small one formed by the tangent across the larger and smaller circles and the chords Z and X. The length given for the part of the chord before X is 2, and that before the chord labelled Z is 5. The length given for the tangent before that labelled Y is 4.

I agree it is confusing. The questions are from a distance learning course that I am doing but are past paper ques apparently.
I'm sorry - I want to help you but I don't want to have to draw the question myself (possibly incorrectly) with quite confusing information.

Can you please take a photo of your materials? Or tell me if you know which past papers these questions come from.
11. Re: IGCSE Question help
12. Re: IGCSE Question help
13. Re: IGCSE Question help
14. Re: IGCSE Question help
The inner walls aren't 6m.

You know pythag? That will give you AB, 3 marks.

The centre of the road is at 7.16 metres, so subtract something from this which will give you another pythag question. So you'll have 7.16^2-(whatever you subtracted)^2= max height^2

Can you do that?

You'd be better drawing some lines and plotting some new points to work it all out.
Last edited by SubAtomic; 08-08-2012 at 16:17.
15. Re: IGCSE Question help
Hi ,

Thanks. I'd got 6m by using Tan45=AB/6. I cannot work out the hypotenuse as all I've got is two angles of 90 and 45 and one side which is 6m. The combinations of Cos 90/Cos45 have given me answers that I know are wrong - (@4m etc).
I've also tried Tan45=x/1.5; Tan45=x/3 etc to find the maximum height. I'm sorry but I've no idea what I would take away from 7.16 (other than the height of the inner wall or the height that I'm trying to find!
16. Re: IGCSE Question help
(Original post by JamalAhmed)
Done
17. Re: IGCSE Question help
(Original post by Arcane Barn Elk)
I'll admit I'm struggling to help you with this one - I'm probably missing something simple. It's definitely not an IGCSE past paper question.

I'll ping some people who've been around recently who may be able to help you:

(Original post by nuodai)
.
(Original post by BabyMaths)
.
(Original post by hassi94)
.
Here's the question again:

(Q14)

Edit Also, it says in your profile that you study at Warwick University but the title of your thread is "IGCSE question help".

Are you studying for an IGCSE while at university? Just interested.
Last edited by notnek; 08-08-2012 at 18:39.
18. Re: IGCSE Question help
(Original post by notnek)
I'll admit I'm struggling to help you with this one - I'm probably missing something simple. It's definitely not an IGCSE past paper question.

I'll ping some people who've been around recently who may be able to help you:

Here's the question again:

(Q14)
This is iGCSE? Damn!

Geometry is not my strong suit but I'll give this some thought.
19. Re: IGCSE Question help
Can x, y, z not be found from what is known from the 2, 4, 5 triangle using Cosine rule and Sine rule throughout? Alternate angles, corresponding angles? Similar triangles? Sorry, just throwing ideas you prob already thought of here
Attached Thumbnails

Last edited by SubAtomic; 08-08-2012 at 19:55.
20. Re: IGCSE Question help
(Original post by Arcane Barn Elk)
Hi ,

Thanks. I'd got 6m by using Tan45=AB/6. I cannot work out the hypotenuse
You are given the hypotenuse, radius, from the centre of that semi-circle no matter what, the radius is the distance between the centre and the curve.

(Original post by Arcane Barn Elk)
Hi ,I'm sorry but I've no idea what I would take away from 7.16 (other than the height of the inner wall or the height that I'm trying to find!
The flat top load is 3 metres wide, the highest point of the tunnel is at the centre, so you'd have half the vehicle on one side of this point and half on the other side. And the middle of the road point is given.