Math geeks - help needed

[MikeyIs4Dcats]

Okay, I should know how to do this, but I don't, and I don't have time to try to figure out the formulas.

I have an arc with a 73' radius. I need to know for an 8' section of that arc, what the midpoint of the arc's distance is from a line across the end points. Or in layman's terms, how much deviation there is in the arc from an 8' line.

Anyone know how to figure this quickly?

 

[JTsyo]

8' line is a cord? Or is the 8' along the circumference?

Assuming its' the cord, drawing it up in ProE gives me .22' between the line and a line tangent to the curve.

 

[TecHNooB]

assuming i read that correctly, R - R cos(angle in radians / 2) might be your answer.

 

[KMc]

If 8' is the arc length, then the distance from it's midpoint to the chord of it's end points is 0.11'

 

[Schfifty Five]

Need moar paintz

 

[David101]

someone check, i didnt even give a second look at it lol

http://img718.imageshack.us/img718/8717/mathsd.jpg

edit: sorry i used 78 instead of 73 by accident and my alpha is supposed to be half of that bottom calculation, my bad just change the numbers

 

[David101]

sorry double

 

[stargazr]

If 8' is the arc length, then the distance from it's midpoint to the chord of it's end points is 0.11'

This is what I got too.

 

[MikeyIs4Dcats]

THanks guys, you are correct, the 8' was the chord length...couldn't remember the term.

 

[KMc]

Well, technically, the answer to your problem is different depending whether the given length of 8' refers to the arc length or the chord length. But because the radius of this arc is so large, with a chord length of 8', the arc length is only 0.004' longer (8.004'). So, the answer comes out to 0.11' either way you do the calculations.

 

[JTsyo]

yea, .11 I had 73 as the Diameter rather than radius.

Distance = 0.109671

 

[MikeyIs4Dcats]

Awesome, thanks guys.

 

[Lemon law]

I was going nuts trying to figure why everyone was saying 0.11 feet were the answer and I kept getting 0.102. Until I realized I was solving for the 78 foot radius and everyone else was solving for 73 feet.