math problem

Do you mean that the box narrows from top to bottom at 10 degrees?

Not sure what you are asking. Do you have a drawing?

-- Gary, East TX -- The longest journey begins with a single step.

no it is a SQ box. just the end tilt

-- Do it right the first time. Becuase fixing it is a wast of time.

from your writing, I am not sure what you mean. Can you do a hand drawing and post it?

-- making sawdust....

i what to now the height of ? before 10deg angle

-- Do it right the first time. Becuase fixing it is a wast of time.

My guess would be 2.114521888” and the 3/4” face will be slightly larger than 3/4 at 0.769840042”

Is this what you had in mind?

Might want to try this on some MDF just to be sure.

-- Leon -- Houston, TX - " I create all my own designs and it looks like it "

I am a bit rusty with my trig but I make it out to be 2.163 or not quite 2-21/128

try doing an actual sized drawing and measuring . . .

fred

-- Fred, Springfield, Ma

I think we are all struggling to understand your diagram. Here is my guess.

sin(x) = opposite / hypotenuse

In this case x = 80 degrees, the opposite side is 0.75”, and you are seeking the hypotenuse.

You can use Google as your calculator…

http://www.google.com/search?q=0.75%2Fsin%2880+degrees%29&btnG=Search

My answer is 0.761569959”

-- Scott, San Diego

thank you swied,

that got the length of the long angel but i am looking for the length of the 90deg.

all so the wright way of fingering it out.

-- Do it right the first time. Becuase fixing it is a wast of time.

I can’t figure out your drawing either. If you could draw it like a blueprint filling in the numbers you
know I could fill in the blanks.

-- Gary, East TX -- The longest journey begins with a single step.

how about this if you had a triangle that was 10-90-90 and one of the 90deg lengths was 3/4 what would be the other. you are looking strait on at a board 3/4 thick standing up at 90deg. then you cut the bottom 10deg.

i want to no how much do i have to measure up to get that 10deg angle

-- Do it right the first time. Becuase fixing it is a wast of time.

The hypotenuse (the length of the angled side) for a 90 degree right angle triangle with an angle of 10
degrees and one side 3/4” is 4.3191”.

The length of the 3 sides would be 3/4” x 4.2535×4.3191

-- Gary, East TX -- The longest journey begins with a single step.

garyk

i do not know how to say this.

-- Do it right the first time. Becuase fixing it is a wast of time.

Okay, you have a box where the vertical sides are 2” high, but one side is tilted 10 degrees. You want to know how tall your angled workpiece should be so that when you cut 10 degrees off of the top and bottom, you are left with a 2” high piece. Correct so far?

AutoCAD says your blank should be 2&5/32” ...

The solid black lines are an endview of your workpiece, the dashed red lines are your cut lines.

If you have trig tables or a calculator that does trig, you can do it that way, but I’m just not up to it today!

-- Coffee is best with a fine layer of sawdust on top. -- http://www.north40custom.com

thank you for the pic. peter

iam trying to do it the long way

-- Do it right the first time. Becuase fixing it is a wast of time.

Partridge, the answer is 70.9276mm or 2 51/64”by trig calc.

-- Grumpy - "Always look on the bright side of life"- Monty Python

The simple way to do this is to break it into triangles (see shaded areas) and use the sine rule to calculate the missing sides. Add together the lengths of A & B on my sketch & you have the answer. I know that is simplified but if you remember your trigonometry from school it’s a snack. A=49/64ths (19.3439mm) B=2 1/32” (51.5837mm), total of 2 51/64” (70.9276mm)
Glad to help anytime.

-- Grumpy - "Always look on the bright side of life"- Monty Python

I’m soooo confused !!!!

-- ??? My mistakes heat the house. It's very warm in here. ???

Grumpy – if the material is 3/4” thick and you tip it 10 degrees, I don’t think you’re going to add nearly an inch in width. You’d have to rotate it more like 28.8 degrees. In your sketch, it looks like you have the piece rotated maybe 20 or 30 degrees (?).

So, now for the math, based on Grumpy’s sketch …
A = tan(10) x .75
A = .1763 x .75
A = .132225

B = 2 / sin(80)
B = 2 / .9848
B = 2.030869

A + B = .132225 + 2.030869 = 2.163094

21/128 = .1640625, which is pretty darn close, but most tapes only read to 32nds.
5/32 = .15625 which is less than .007 off – close enough to sand.

So I’m sticking with 2 5/32”.

-- Coffee is best with a fine layer of sawdust on top. -- http://www.north40custom.com

Sorry Pete. I agree with you 2 5/32”. I put the wrong angle in the calculations.

-- Grumpy - "Always look on the bright side of life"- Monty Python

Yay! Grumpy and I got the same answer, so it must be right!

-- Coffee is best with a fine layer of sawdust on top. -- http://www.north40custom.com

Good job to the LJ mathematicians!!!!!!! Oh yes ….Next I suppose youse guys will be splaining the philosphy of the 3-4-5 rule …

-- Mike in Bonney Lake " If you are real real real good your whole life, You 'll be buried in a curly maple coffin when you die."

Philosophy now, huh?

ahem …
Based on the posits and theories of the ancient Greek philosopher and mathematician Pythagoras, the 3-4-5 rule is not so much a “rule” per se, as it is a deep and personal understanding of the true nature of the balance and rhythm of the world around us …

-- Coffee is best with a fine layer of sawdust on top. -- http://www.north40custom.com

Don’t Knock the 3-4-5 rule Jocks. We would be lost without it. LOL.
How about this one.
To find the area of an irregular triangle when you know the lengh of the 3 sides but not the angles.
Area = square root of [s(s-a)(s-b)(s-c)] where s=1/2 the perimeter & a,b&c are the lengths of the 3 sides.
Ok Jocks, lets see what else you have stored in the memory cells.

-- Grumpy - "Always look on the bright side of life"- Monty Python

Do you guys realize that while you’re Pythagorizing your time away, there’s wood in your shop waiting to become something?

-- Sir Robert

thanks gain LJ…....

-- Do it right the first time. Becuase fixing it is a wast of time.