# Thread: What is the length of this dimension?

1. Member
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Dec 2018
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## What is the length of this dimension?

This is the desired diagram: Fig 3.30 (original).JPG.

This is what I did in CATIA: Fig 3.30_1.JPG

What is the length of this marked dimension?

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2. Moderator
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First of all, I want to commend you Kingston on the sketch you have drawn. Finally, the lines are green indicating they are fully constrained. I also see all the little H and V and other symbols that were missing on your previous sketches. Good job on this!

1. To answer your specific question (based on the attached figure) requires that we do a little trigonometry. The angle is 30 deg. The horizontal length of the chamfer is 88 - 78 = 10mm. Using the cosine function, we can calculate the length = 10 / cos 30 = 11.547mm approx.

2. Using CATIA, a better way to determine the length is to draw the left-most line 88 mm from the right side. Trim the left-most line and the 30 degree line to each other, and you will have the exact length determined automatically. (if you want, you can measure the length of the line and compare it to what we calculated above)

3. If this part is like the others you have been working on recently, there is probably a 3-view drawing that you didn't attach to your post. If you look closely at the 3-view drawing, I think you will find that chamfer is dimensioned. (In the future, please include pictures of the complete drawings you are working with)
Last edited by MrCATIA; January 20th, 2019 at 03:44 PM.

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3. Member
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Originally Posted by MrCATIA
The horizontal length of the chamfer is 88 - 78 = 10mm. Using the cosine function, we can calculate the length = 10 / cos 30 = 11.547mm approx.
What is that formula you have used for calculating the length of chamfer?

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4. Moderator
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I used the trigonometry formula for the cosine: cos θ = Adjacent length / Hypotenuse length