# How to form an arc

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## How to form an arc

 Hi, I’m gradually learning to use this software but am stuck in trying to insert an arc at a particular point. It’s a little difficult to explain but I’m attempting to form an arc that touches (a) a horizontal baseline and (b) the edge of an adjacent arc. The purpose of the arc that I am attempting to apply is that it will form a predetermined shaped curve between ‘a’ and ‘b’. To get the required shape in proportion it specifies that the radius of the arc be 1 inch, 25.4mm and this is the problem that I have. I’m having difficulty in determining the radius point in relation to the two points so as to draw the arc. I’m sure that there must be a way of achieving this, but after many failed attempts I’m seeking some help.
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## Re: How to form an arc

 Hmm, I'm not sure what you are trying to describe.  I've attached an image - is it something like this? More generally, if the Arc tools [] don't provide what you need, you can create some construction lines and work from the intersecting lines and /or arc centres?
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## Re: How to form an arc

 Hi Gary, Yes, that’s exactly what I mean. I’m looking for a method that is straight forward to execute. I’ve tried vertical the horizontal lines method, but it seems like a hit and miss exercise
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## Re: How to form an arc

 Depending on the exact conditions, there might not be a geometric solution with one arc only. Can line A be enlongated / shortend, can a strait line be appended to the existing arc? You could provide a dxf with the entities in question.
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## Re: How to form an arc

 In reply to this post by spike Okay, given you know the location of line (a) and arc(b).  The easiest way is to fillet it (Tools -> Modify -> Fillet, and specify a 1" radius).
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## Re: How to form an arc

 Thanks for that Gary will given it a go some time tomorrow
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## Re: How to form an arc

 In reply to this post by dellus Hi The image is as Gary has illustrated. I'm producing from an existing plan (on paper) with the intention of eventually applying it and other projects using CNC. I've always used Corel Draw for graphics in the past, which is a breeze to use, but CAD is a little different.
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## Re: How to form an arc

 In reply to this post by Gary S  Worked a treat, just what I was looking for. Thanks