# Thread: Calculate Chord w/o Known Angle at Circumference

1. ## Calculate Chord w/o Known Angle at Circumference

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What I'm trying to do
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Determine the end of my cut.
Using a ruler easy takeoff .
Can it be done mathmatically?

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Problem
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I have a 10 inch saw blade. The radius in naturally 5 inches.
I want to measure down a distance (can be any but say 1/4 inch) from the circumference (top of the blade)
to the table top. From this right angle intersection, I want to measure the distance to the blade (circumference)
where it intersects the table top.

2. ## Re: Calculate Chord w/o Known Angle at Circumference

I think this is what you are trying to do, where x is the measurement from the top of the blade to the tabletop.
To find w you need to use Pythagoras' Rule.
$\displaystyle w^2 + (5-x)^2 = 5^2$
Can you rearrange that to get a formula for w?

3. ## Re: Calculate Chord w/o Known Angle at Circumference

Debsta:

Thanks for your efforts on my behalf.
Now that I see what was done, makes sense.
Re: In terms of w:

w = sqrt(25 - ((5 - x) * (5 - x))

or general formula of: