Calculation Help!

[camaro1969]

Thought I knew math but can't figure it out...

I'm going to build a staircase with beveled corners and need help calculating the angles a b c,

Then L1 L2 L3

And how long will X and Y be


Something is going wrong...

The miters should be 22.5 degrees, right?

 

[camaro1969]

Or will the temperatures be 30??

 

[13th Marine]

a = b = c = 90/3
And the edge becomes 60 degrees, but if you cut at 30 degrees it will be correct.

For the other pieces, you need to use some trigonometry, i.e., sine and cosine.

 

[claym]

Should be 30 degrees, given that you want symmetry, which I assume

Then, cos(30) = 204/y
i.e., y = 204/cos(30)

Sin(30) = L3/y
i.e., L3 = y*sin(30)

 

[richardtenggren]

X=Y=204xCos(30)=177 cm
L1=L3=204xSin(30)=102 cm

L2 is obtained by 204-L2=102 cm
L2=sqrt(102^2+102^2)=144 cm
You can also take 102/cos(45)

Edit: a bit slow to write

 

[camaro1969]

Yes 30 degrees on a b c,
There's the first thought error.

But then it should be 90 degrees at the top right and bottom left,
Now picture with updated values

 

[Talvan]

a = b = c = 90/3
And the frame will be 60 degrees, but if you cut with 30 degrees it will be correct.

For the other pieces, you need to use some trigonometry, i.e., sine and cosine.

It's not certain, it depends on how he wants it.

 

[13th Marine]

Based on the drawing and description, I interpreted it as...

 

[camaro1969]

New image

 

[Talvan]

New picture

It's very easy, it's just symmetry plus and minus

 

[13th Marine]

No, you won't solve that without trigonometry.

 

[Robert-san01]

Draw it in CAD...

 

[camaro1969]

X=Y=204xCos(30)=177 cm
L1=L3=204xSin(30)=102 cm

L2 fås genom 204-L2=102 cm
L2=sqrt(102^2+102^2)=144 cm
Man kan ta 102/cos(45) också

Edit: lite seg på att skriva

Will try these measurements
I've completely forgotten this math...

 

[camaro1969]

Draw it up in CAD...

Going to build today..
Cad available tomorrow

 

[13th Marine]

Will try these measurements
Have completely forgotten this math...

Yes, trigonometry is something even I, as an electronics engineer, use too infrequently to remember it.