News:

And we're back!

Main Menu

Anyone good with maths (trigonometry) here?

Started by viper37, June 08, 2017, 04:25:06 PM

Previous topic - Next topic

viper37



I'm looking to find X and Y.

Angles on the 20m side are 90deg.  The angle between 3,66m and the base is 45deg.

The distance between Y and the end of the shape is approx, 1,520m so let's use this value to determine the real length of this top side: 12,23m.

How do I find X and Y's height?
I don't do meditation.  I drink alcohol to relax, like normal people.

If Microsoft Excel decided to stop working overnight, the world would practically end.

The Brain

I've settled a few problems of triggernometry in the court of judge Colt and his jury of six, sure.
Women want me. Men want to be with me.

CountDeMoney

My math classes we just a blur of trying to read books under my textbook, and achingly long boredom boners.

Maximus

So the angle on the top left is not 90 degrees as shown? Or to what are you referring as the base?

Maladict

Find out the scale of the drawing and then just measure it.

Oexmelin

#5
Tu es sûr que la mesure de ton angle à la base est de 45? Parce qu'avec ces mesures, ça donne plutôt un angle de 79 degrés.

Pour rappel, le tan de l'angle à la base, c'est le rapport du côté opposé (20) sur le côté adjacent (3,66). 

Edit: Et si l'angle est bien 79,46 alors y vaut environ 28 cm, et x, environ 2.51 m.
Que le grand cric me croque !

viper37

#6
Quote from: Oexmelin on June 08, 2017, 06:23:17 PM
Tu es sûr que la mesure de ton angle à la base est de 45? Parce qu'avec ces mesures, ça donne plutôt un angle de 79 degrés.

Pour rappel, le tan de l'angle à la base, c'est le rapport du côté opposé (20) sur le côté adjacent (3,66). 

Edit: Et si l'angle est bien 79,46 alors y vaut environ 28 cm, et x, environ 2.51 m.
le dessin n'est pas à l'échelle, je l'ai fait moi même.  ça n'est possiblement pas 45 degrés, mais bon, je le mesurerai.  ça aurait été plus simple si l'ingénieur m'avait donné les mesures... <soupir>

Je croyais que la tangente ne valait que pour un triangle rectangle parfait et non pour un polygone irrégulier?

Je vais voir demain avec le dessin imprimé, ou idéalement, si l'ingénieur peut me donner les vraies mesures cette fois-ci.


@Maximus: top left is 90 degrees.  Bottom left, let's assume it's 79 degrees as Oex said, I'll measure it on the printed plans since my softwares can't give me angles or measurement for such drawings.
I don't do meditation.  I drink alcohol to relax, like normal people.

If Microsoft Excel decided to stop working overnight, the world would practically end.

viper37

Quote from: Maladict on June 08, 2017, 05:20:21 PM
Find out the scale of the drawing and then just measure it.
I do not have this elevation on the drawing.  I made it myself with a free cad software.  My skills... lie elsewhere than in drawing :P

All it says is "variable height".  If it was that simple, I would have done it by finding the scale (it isn't even written <sigh> ) :)

Usually, engineers give me a nice view and they give me the height at each side.  This one... well, neither the client nor his engineer seems to know exactly what they want.
I don't do meditation.  I drink alcohol to relax, like normal people.

If Microsoft Excel decided to stop working overnight, the world would practically end.

Ed Anger

Quote from: CountDeMoney on June 08, 2017, 04:30:20 PM
My math classes we just a blur of trying to read books under my textbook, and achingly long boredom boners.

I dreamt of DeAnna Zimmer who sat in the seat in front of me. Hot as hell and had these long legs that.....

Excuse me. Sorry Viper.
Stay Alive...Let the Man Drive

DGuller

I don't think your graph works, unless I'm misunderstanding something.  If the bottom left angle is 45 degrees, the black line at the bottom should be crossing the top line 3.66 m in, yet in your picture it doesn't cross it even after 20 meters.

Maximus

Quote from: DGuller on June 08, 2017, 08:05:46 PM
I don't think your graph works, unless I'm misunderstanding something.  If the bottom left angle is 45 degrees, the black line at the bottom should be crossing the top line 3.66 m in, yet in your picture it doesn't cross it even after 20 meters.
I think he was saying the top left angle is 45 degrees, but not sure.

Oexmelin

Quote from: Maximus on June 08, 2017, 08:44:43 PM
I think he was saying the top left angle is 45 degrees, but not sure.

He is saying he was told the bottom left angle is 45, but, as I have told him, it doesn't work with the rest of the measurements, assuming the top left angle is indeed 90.
Que le grand cric me croque !

frunk

Assuming the 45 degree angle thing is a red herring, you can get the values without really knowing Trig since you don't care about the angles.

3.66/20 = .183

That's the ratio of height to length.

x/(20-6.25)=.183
x=13.75*.183=2.51625

y/1.52=.183
y=1.52*.183=.27816

x=2.51625
y=.27816

Which I think is what Oex said above.

DontSayBanana

There's no way the info you've given us adds up.

Given the two legs of the right triangle, the tangent tells me the non-square angle of the 3.66m line is 79.6296 degrees, not 45.

Furthest I can get with the dimensions given is that the distance of the hypotenuse from the 3.66m side to where it meets line X is 6.3538m. Since the two lines run parallel, there doesn't seem to be any way to figure out how far up or down the legs the 6.25m measure line is.
Experience bij!

frunk

Quote from: DontSayBanana on June 08, 2017, 09:32:00 PM
There's no way the info you've given us adds up.

Given the two legs of the right triangle, the tangent tells me the non-square angle of the 3.66m line is 79.6296 degrees, not 45.

Furthest I can get with the dimensions given is that the distance of the hypotenuse from the 3.66m side to where it meets line X is 6.3538m. Since the two lines run parallel, there doesn't seem to be any way to figure out how far up or down the legs the 6.25m measure line is.

The green lines are the measurements, they aren't part of the shape.