Announcement

**pgk** · 03-20-2006, 01:48 PM

Burn,

I'm not to good at math either, but if I remember I'll ask my son when I get home tonight. I alway's joke around with him asking if he want's help doing his home work, thank God he always say's no thanks dad Iv'e got it covered. He's in 10th grade and doing 12th grade math and setting the curve for the class.

Pete

**jolane** · 03-20-2006, 01:50 PM

No Problem. Here you go:

Because this is a right triangle, you can use trig (Sine, Cosine, Tangent). The easiest way, IMO (there are a few), is to use Tangent since you know the two sides accurately (the hyp will be rounded).

Tangent(angle) = (Opposite Side)/(Adjacent Side)

So: Tangent (angle) = 1.875/3.375 = 0.5555

Angle = Inverse Tangent (0.5555) = 29.0546 degrees

The other angle is: Inverse Tangent (3.375/1.875) = 60.9454

The other way to find the last angle is: 180 - 90 - 29.0546 = 60.9454

I hope this helps, and is not too confusing. You will need a scientific calculator to figure this out. Normally Inverse Tangent is evaluationed by a 2nd Function button then press Tan.

If you still have questions, I will be happy to try to explain this better, but it will have to be this evening at the earliest.

Joshua

EDIT: BTW, if you have a Machinery's Handbook, it is in there under Tangent also. Page 88 of the 27th Edition.

**Coalsmoke** · 03-20-2006, 01:50 PM

math = 29.05* and 60.95*, your protractor is on the money. Are you sure you got everything else correct?

**katiebo** · 03-20-2006, 01:56 PM

The resultant angles are 29.0551 and 60.9470. I use the sine of the angle = the opposite leg divided by the hypotenuse. In the case of the first angle ( I called it "a") sin (a) = 1.875/3.8608. Then, taking the arcsine of 1.875/3.8608 (commonly labeled "asin") results in the desired angle.

A quick and dirty way to remember which sides will yield the sine, cosine and tangent of a desired angle is (not don't laugh) Cheif SohCahToa. Sin (a) = opposite leg/hypotenuse. Cos (b) = adjacent leg/ hypotenuse. Tangent (c) = opposite leg/ adjacent leg. The resultant angle will be determined useing the appropriate asin, acos or atan as I did above.

Hope this helps.

**burninbriar** · 03-20-2006, 02:02 PM

Thanks a lot guys. That doesnt seem to be enough to make a differance. When I line up individual parts of the layout every thing fits , so I'm pretty sure my proceedure is right. When I start puting the parts together to compleete the layout it gets progrssively more out of wack. I might just have to double check the positioning of every thing.
Thank you again, at least now I know where I stand on the angles.

**katiebo** · 03-20-2006, 02:12 PM

The error accumulation can be a killer. How many parts do you have to put together?. Is this going to be a dome or something like that?

**burninbriar** · 03-20-2006, 02:14 PM

Good news. I multiplied the amount I was off, .05 , by the number of times I used it and came out to the amount I'm off by.
The bad news is I have to start over now. Also thanks for takeing the extra effort to explain it to me. I'm going to do a few problems and see if I got it and write this info down as I use angles a lot.

**burninbriar** · 03-20-2006, 02:21 PM

Originally posted by katiebo

The error accumulation can be a killer. How many parts do you have to put together?. Is this going to be a dome or something like that?

Its a rectangular headlight bucket with 7/8" radious corners and a sloped top. There is a lot of angling involved and I dont mean fishing. Once I get the layout done I plan to take pictures of the progress and post it hear. All my latest threads relate to this project. You might have seen the one where I made the radius attachment for the brake. The post with the antique equipment was a result of working on this project.

**burninbriar** · 03-20-2006, 03:05 PM

I can follow this to the point of tangent angle = oposite side / by adjacent side and get .5555, then I'm smoked. I'm going to have to get my buddys daughter to teach this to me. Thanks for the effort.

**katiebo** · 03-20-2006, 03:15 PM

Are you using a scientific calculator?

**drscotch** · 03-20-2006, 03:25 PM

A lot of people have a scientific calculator and don't even know it. Open the Windows calculator (Start|Programs|Accessories|Calculator) and choose View|Scientific from the menu bar (click the Inv check box to get the inverse functions). Voila, you've got the trig functions you need. For free, sorta.

Here's a quick and dirty web triangle calculator:
http://www.machinist-calculator.com/...angle-Eng.html

If you google 'basic trigonometry' there are lots of really good sites that will step you through the theory using graphics which makes it much easier to follow than text. Hope this helps.

**burninbriar** · 03-20-2006, 03:48 PM

katiebo :
No I wasnt useing a scientific calculater.

drscotch :
No , I didn't know it was there and yes it is there. I'll have to give this another shot.

**burninbriar** · 03-20-2006, 04:10 PM

OK !!!!
I got it now.

I think I'll still have my buddys daughter teach me more about the theory but this is enough to get me started. I'll tell you what, no math past the 8th grade hurts. When I was doing sign work I came up with a way of figureing angles compleetly differant than the correct way, but it worked. Once I learned from my brother the right way to figure angles it got a lot easyer. I was starting with a flat peice of sheet metal and calling it 0 degrees when I should have been calling it 180. The meathod I developed worked but it was not near as easy to use as the right way.
I hate to keep repeating myself but thanks again.

**barnett64** · 03-20-2006, 06:40 PM

here are 2 great books on the type of math we (pipefitters at least) use all the time, very easy to understand and not too expensive.

http://www.pipefitter.com/mtbo.html
http://www.pipefitter.com/pfmg.html

Announcement

Math help needed for layout. Please.

Math help needed for layout. Please.

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment