2
$\begingroup$

I am trying to find out the height of the wall for my poly-tunnel construction. Can you please let me know what the height of the the wall will be? enter image description here

Update

Maybe the image below is the correct one. I want a lean-to roof with 15 degrees.

enter image description here

Update

I made some more research and I think the below image is what i want.

enter image description here

  • 0
    Have you tried anything? – 2017-01-13
  • 0
    @ParclyTaxel I don`t know where to start – 2017-01-13
  • 0
    Are you sure that that angle is $15^\circ$? Because that would make the opposite wall have negative height. – 2017-01-13
  • 0
    @Arthur Yes, I am sure. What do you mean negative height? It will certainly be less than 4 meters. – 2017-01-13
  • 1
    I mean it will be below ground. If the angle is $75^\circ$, on the other hand... – 2017-01-13
  • 0
    Taking to acount your picture the height would be $4-10\cos 15º<0$. – 2017-01-13
  • 0
    Maybe I put the angle at the wrong place. Maybe 15 degrees should go to the other wall... – 2017-01-13
  • 0
    I have updated my question and added another image – 2017-01-13
  • 0
    You'd better study some trig rules, instead of asking here. – 2017-01-13
  • 0
    @Aretino it has been a very long time since I left school. I think i am too old to study... – 2017-01-13
  • 0
    Read here: http://www.mathopenref.com/trigtangent.html – 2017-01-13
  • 0
    @Aretino According to that my short side should be 1.32 meters. But that is too short. Am I doing something wrong? – 2017-01-13

1 Answers 1

0

enter image description here

Let's make $DE \perp AE$. Then:

$$\tan 75°=\frac{DE}{AE}=\frac{10}{AE}=\tan(45°+30º)=\frac{\tan45°+\tan 30°}{1-\tan45°\cdot\tan 30°}$$

Now you can find $AE$ and then:

$$CD=BE=4-AE$$

Can you finish?

  • 0
    @baris: is it clear? – 2017-01-21