angles: trig help

I want to double check some wedges I've made for angled cuts. In a 24" long wedge, how much gain on the square corner is there for each degree of angle?

I know the method is rattling around back there amongst the unused and as yet unkilled brain cells but I can't seem to come up with it.

Thanks to the more mathmatically inclined.

jc

Reply to
Joe
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Joe wrote: | I want to double check some wedges I've made for angled cuts. In a | 24" long wedge, how much gain on the square corner is there for | each degree of angle? | | I know the method is rattling around back there amongst the unused | and as yet unkilled brain cells but I can't seem to come up with it. | | Thanks to the more mathmatically inclined.

It's not the same for each degree of angle (the gain going from 0 to 1 degree is a lot larger than the gain when you go from 88 to 89).

Since the tangent of an angle (a) is equal to the rise (y) divided by the run (x=24), you can calculate:

tan(a) = y / 24

y = 24 * tan(a)

If a1 is your starting angle then

y1 = 24 * tan(a); and y2 = 24 * tan(a+1)

and the gain for that 1 degree difference is

y2 - y1 = 24 * (tan(a+1) - tan(a))

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Reply to
Morris Dovey

| It's not the same for each degree of angle (the gain going from 0 | to 1 degree is a lot larger than the gain when you go from 88 to | 89).

I think I said that backward. :-(

larger --> smaller

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

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Reply to
Morris Dovey

I am not going to attempt ASCII art.

If by the "square corner" you mean the two sides of a right angle triangle which are orthogonal (90 degree angle between these sides, then the formula is

Height = Length * Tangent(opposite angle).

For Length = 24 inch and opposite angle = 1 deg, then Height = 0.418922

If you have MS Excel, then you can enter a formula Cell for Height = =Cell for Length*TAN(RADIANS(Cell for angle))

For some strange reason MS designed Excel to use RADIANS in angle functions instead of degrees where 180 deg = PI Radians.

Dave Paine

Reply to
Tyke

As Morris Dovey warned in a separate message, the height is not linear for each degree. Hence you do need to use the formula.

Dave Paine

Reply to
Tyke

Assuming the 24" side is included between the right angle and the angle to be incremented, and the 24" side and the 'gain' side are at right angles to each other:

Gain in inches = 24*tangent(incremented angle).

For some angles: 1 deg-> .4189516" 2 deg-> .8380985 15 deg -> 6.4307806" 22.5 deg-> 9.5941125" 30 deg -> 13.8564061" 45 deg -> 24.0000000" 89 deg-> 1,374.9590791" etc.....

Using Windows calculator makes the computation easy once you know the equation.

Tin Woodsmn

Happy New Year to all of the Wreckers....

Reply to
TinWoodsmn

What do you mean by "gain" ? If you mean, for a right triangle with angel A between the hypotenuse and a 24" side, that the "gain" is the length of the side opposite angle X, then the change in the length of that side is not a linear function wrt the angle X. However, it will be equal to 24 X sine(A)

Reply to
lwasserm

OOPS, maybe a little doubt would be good on this one. G/HYP does = SIN X, but you have two unknowns, since the base is fixed at

Reply to
Wilson

You are right, I was mixing up my sides, the tangent is correct.

Reply to
lwasserm

Funny story on that subject:

On of my aspiring architectural drafters was trying to make a model of his project with a 6/12 roof slope. The roof just wouldn't work out.

After lots of investigation, I found out that he had reasoned that if a

12/12 slope gives a 45 degree angle, a 6/12 should give a 22.5 degree angle. He just couldn't see my arguments to the contrary.

The only way I convinced him was to ask him to draw a roof slope at 24/12, and see if it produced a 90 degree angle....

Old Guy

Reply to
Old guy

Thanks everyone for the help. In the original post, I neglected to mention that I was calculating this for the first couple of degrees. I've got it now.

Have a very happy and healthy New Year.

jc

Reply to
Joe

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