My maths is shocking

WeegyAVLover

Distinguished Member
In my defence I have had no real need for trigonometry since high school or at least that is my defence & I am sticking to it.

So here is what I am dealing with.

I have one post at its lowest will be:
65cm
Another post at its highest will be:
80cm
The distance between them will be:
90cm

I have been trying to figure out what the angle is I would need to make but I cannot get it.

Anyone able to help me understand what I need to do to get the answer without giving me the answer?

Shameful... I know.
Thanks
 

blue max

Distinguished Member
What are you trying to do or make weegie? Why do you need to know the angle. I'd just cut a 15cm piece of timber and a 90cm piece and mark the board to cut if that's what you are doing. You could just measure it 15cm up and 90 along and draw the line with a straight edge too.
 

nheather

Distinguished Member
I can't entirely picture what you are saying because of the mix of highest and lowest. Also whether the distance between them is the horizontal or diagonal.

If we assume that one post is 65, the other is 80 and there is 90 between them horizontally, then you can work out the angle between the tops of the post by thinking of them as one post of 0cm and the other of 80-65=15cm.

Then you have a rise of 15cm over 90cm.

Tan(angle) = 15/90 = 0.1666

Angle = 9.5 degrees

Cheers,

Nigel
 

WeegyAVLover

Distinguished Member
Tan(angle) = 15/90 = 0.1666

Angle = 9.5 degrees

Cheers,

Nigel
Right I got the 0.166 answer.

How in sweet Jesus does that equate to 9.5 degrees?

Blue Max I love the simplicity of your idea & may use it but this bugging me so much I need to know trigonometry now.

I am building " Logstore v2.0 " and was wanting the angle for the roof.... You know me pictures will follow
 

nheather

Distinguished Member
Right I got the 0.166 answer.

How in sweet Jesus does that equate to 9.5 degrees?

It uses tangents from trigonometry. If you look at this picture

triangle_2.png


One of the trigonometry functions is Tangent which is simply Opposite/Adjacent

So the Tangent of x degrees is equal to Opposite/Adjacent

TAN(x) = O/A = 15/90 = 0.1666

Now you need a calculator because you need to use the Inverse Tangent function (usually labelled something like Tan(x)-1) which simply means "tell me what angle would result in a tangent of 0.1666).

Doing that gives 9.5 degrees.

Cheers,

Nigel
 

nheather

Distinguished Member
Nigel,
Thanks.
I did not realise you needed a calculator to convert what the 0.1666 output was in degrees.

Thanks again.

A tangent is just a glorified lookup table. A list of angles, along with how they would be expressed as a gradient. Indeed when I went to school I did have to use a book of tables for this sort of stuff.

The trouble with trigonometry is that it is pretty straightforward but it is beset with stupid names like trigonometry, opposite, adjacent, hypotenuse, sine, cosine, tangent with make seem a lot more complicated than in actually is.

Cheers,

Nigel
 

Pisto_Grih

Distinguished Member
The trouble with trigonometry is that it is pretty straightforward but it is beset with stupid names like trigonometry, opposite, adjacent, hypotenuse, sine, cosine, tangent with make seem a lot more complicated than in actually is.

The trouble is that we learn it when we're 13/14 and the first time many of use need to use it is when we're building log stores as an adult! :D
 

nacmacfeegle

Distinguished Member
Nigel,
Thanks.
I did not realise you needed a calculator to convert what the 0.1666 output was in degrees.

Thanks again.

If you are of a certain age, you would look up a Log Table, which also had Tan, Cos, Sin look ups in it....:blush:

You don't need to know the angle Weegie, a 9.5 degree slope will be plenty to ensure the water comes off the roof. Even faced with Scottish west coast rain.

Edit:- BTW looking forward to the Warriors game tonight....
 

IronGiant

Moderator
I seem to remember us doing this when Logstore v1.0 was being designed :D
 

WeegyAVLover

Distinguished Member
If you are of a certain age, you would look up a Log Table, which also had Tan, Cos, Sin look ups in it....:blush:

You don't need to know the angle Weegie, a 9.5 degree slope will be plenty to ensure the water comes off the roof. Even faced with Scottish west coast rain.

Edit:- BTW looking forward to the Warriors game tonight....

When it comes to straight math I am fairly good. Anything that you do not use that often like trig has been cufuffled :)

Yeah I do not get to see those games much but will be listening on the radio if I can. Big ask for Warriors against Munster... I know Glasgow finished higher but... We shall see
 

WeegyAVLover

Distinguished Member
I seem to remember us doing this when Logstore v1.0 was being designed :D

Your memory is the bane of my existence :)

You are correct but somebodies 4yr old told me the measurements I needed then but it was done in a different way. I also wanted to understand how it was done... Besides having another thread that confirms my stupidity and allows people people to "tut" "roll their eyes" and say "sheeeesh... What a Muppet!".... is always good fun :)
 

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