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# Can anyone help me with this maths question? watch

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2. What exactly do you need help on?

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3. Find the length pr in the photo u sent

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4. (Original post by Minzky)
Find the length pr in the photo u sent

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Calculate the length of each of the 4 base parts then apply pythagorous.
5. Pythagoras is for right angle triangles though?
6. (Original post by Minzky)
Pythagoras is for right angle triangles though?
APR is a right-angled triangle.
7. (Original post by Aph)
APR is a right-angled triangle.
No it isnt
8. (Original post by Aph)
Calculate the length of each of the 4 base parts then apply pythagorous.
How would you find each base part

If you could do that then you would know AP so you would know AR
9. (Original post by TenOfThem)
No it isnt
Yes it is
(Original post by TenOfThem)
How would you find each base part

If you could do that then you would know AP so you would know AR
the lines AB and BC are the same length and the angles are the same across the line as each part is the same length you know all the base parts are the same length.
10. (Original post by Aph)
Yes it is
the lines AB and BC are the same length and the angles are the same across the line as each part is the same length you know all the base parts are the same length.
You are mistaken regarding the right angled triangle ... The angle BAC is not 45 degrees

Regarding the base parts ... I can not see any easy way to calculate them ... Perhaps you can suggest a method
11. (Original post by Aph)
Yes it is
No it really isn't.
12. (Original post by TenOfThem)
You are mistaken regarding the right angled triangle ... The angle BAC is not 45 degrees

Regarding the base parts ... I can not see any easy way to calculate them ... Perhaps you can suggest a method
I never said it was but APR is. That's what I said.

its simple can you not see that the lines AP=R(dotted line) because they are identical triangles but RB(dotted line) is sitting on a square so that the bases are the same?!
13. (Original post by Phichi)
No it really isn't.
Look ate the similar triangles
14. (Original post by Aph)
I never said it was but APR is. That's what I said.
APR is an isosceles triangle, the angle is not 45 ... Can you explain why you think it is right angled
15. (Original post by Aph)
its simple can you not see that the lines AP=R(dotted line) because they are identical triangles but RB(dotted line) is sitting on a square so that the bases are the same?!
This does not actually make sense

If the angle APR were 90 degrees then the base would be split equally into 4.5cm
But it isn't ... So I am still wondering how you are working out the base lengths
16. (Original post by Aph)
APR is a right-angled triangle.
It really, really isn't. Read the question again.
17. (Original post by TenOfThem)
APR is an isosceles triangle, the angle is not 45 ... Can you explain why you think it is right angled
ABT is right angled agreed? And APR is a similar triangle correct? Because it has a common angle PAR and has sides of proportional dimension as AB=10 and AR=5
you know the roof is symmetrical so AT=AC, AC=18 so AT=9
and AT=2AP
18. (Original post by Aph)
ABT is right angled agreed? And APR is a similar triangle correct? Because it has a common angle PAR and has sides of proportional dimension as AB=10 and AR=5
you know the roof is symmetrical so AT=AC, AC=18 so AT=9
and AT=2AP
No

APR is not a similar triangle

It has one common angle ... And one pair of proportional sides

It could only be similar if APR were right angled and we have established that it is not
19. (Original post by Aph)
AT=2AP
Just because it looks roughly like that in the picture does not mean it is true...
20. (Original post by TenOfThem)
No

APR is not a similar triangle

It has one common angle ... And one pair of proportional sides

It could only be similar if APR were right angled and we have established that it is not
Sorry I missed that AP=PR
but as APR shares that angle with ABC would it not be fair to say that the scale factor between AB and AC would be the same as that between AP and AR.

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Updated: January 24, 2015
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