# How to extend an arc

**URL:** <https://discourse.shapr3d.com/t/how-to-extend-an-arc/29185>\
**Category:** Modeling Questions\
**Created:** [December 4, 2023, 2:49pm UTC](https://discourse.shapr3d.com/t/how-to-extend-an-arc/29185 "2023-12-04T14:49:54Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![jcclow](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/jcclow/32/23888_2.png) [@jcclow](https://discourse.shapr3d.com/u/jcclow)\
**Post date:** [December 4, 2023, 2:49pm UTC](https://discourse.shapr3d.com/t/how-to-extend-an-arc/29185/1 "2023-12-04T14:49:54Z")

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I am using 5.520.6147.0 #9d8cd91e on a Windows PC.

I have an arc that needs to be extended to meet another line. I do not see a way to maintain the diameter of the arc while extending the arc manually by dragging the endpoint. When I click on the arc, the purple guideline that appears has the same radius as the arc I am trying to extend, but as soon as I click on the point to move it, the purple guideline changes to align with the X-Y plane and when I drag the point the diameter of the arc changes.

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**Author:** ![Bob3DPO](https://avatars.discourse-cdn.com/v4/letter/b/7993a0/32.png) [@Bob3DPO](https://discourse.shapr3d.com/u/Bob3DPO)\
**Post date:** [December 4, 2023, 3:12pm UTC](https://discourse.shapr3d.com/t/how-to-extend-an-arc/29185/2 "2023-12-04T15:12:03Z")

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Hi Jeremy,  
Try this:

- lock the line
- select endpoint of arc
- select **coincident** method

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**Author:** ![jcclow](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/jcclow/32/23888_2.png) [@jcclow](https://discourse.shapr3d.com/u/jcclow)\
**Post date:** [December 4, 2023, 3:31pm UTC](https://discourse.shapr3d.com/t/how-to-extend-an-arc/29185/3 "2023-12-04T15:31:00Z")

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Hey Bob,

Well duh! That is the hardest part of swapping between AutoCAD, Sketchup and Shapr3D…the constraints. Your tip worked perfectly.

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**Author:** ![Bob3DPO](https://avatars.discourse-cdn.com/v4/letter/b/7993a0/32.png) [@Bob3DPO](https://discourse.shapr3d.com/u/Bob3DPO)\
**Post date:** [December 4, 2023, 5:09pm UTC](https://discourse.shapr3d.com/t/how-to-extend-an-arc/29185/4 "2023-12-04T17:09:05Z")

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Great! I’m glad I could help.