# How do I draw a 2D triangle with fixed side lengths, angles unknown

**URL:** <https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925>\
**Category:** Modeling Questions\
**Created:** [May 21, 2023, 12:18am UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925 "2023-05-21T00:18:36Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![DesertDave](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/desertdave/32/18343_2.png) [@DesertDave](https://discourse.shapr3d.com/u/DesertDave)\
**Post date:** [May 21, 2023, 12:18am UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/1 "2023-05-21T00:18:36Z")

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I need to extrude a triangular shaped bar but first I need to draw the triangle profile. It has sides 152mm x 183mm x 112mm. Is there I way I can do that without having to calculate what the angles are first?

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**Author:** ![TigerMike](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tigermike/32/32650_2.png) [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)\
**Post date:** [May 21, 2023, 2:03am UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/2 "2023-05-21T02:03:45Z")

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**Author:** ![Oregonerd](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/oregonerd/32/8012_2.png) [@Oregonerd](https://discourse.shapr3d.com/u/Oregonerd)\
**Post date:** [May 21, 2023, 6:17am UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/3 "2023-05-21T06:17:56Z")

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Tiger Mike’s way is excellent. Another way is to simply sketch 3 connected lines and resize them respectively.

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**Author:** ![Eableson](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/eableson/32/10848_2.png) [@Eableson](https://discourse.shapr3d.com/u/Eableson)\
**Post date:** [May 22, 2023, 1:59pm UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/4 "2023-05-22T13:59:47Z")

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Some techniques never go out of style. Was using this kind of thing for woodworking stuff ages ago, but had forgotten it until I saw your animation here.

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**Author:** ![TigerMike](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tigermike/32/32650_2.png) [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)\
**Post date:** [May 22, 2023, 3:21pm UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/5 "2023-05-22T15:21:57Z")

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Yes indeed. This is basically 8th grade Drafting 1, using ruler and compass.

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**Author:** ![Istvan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/istvan/32/23668_2.png) [@Istvan](https://discourse.shapr3d.com/u/Istvan)\
**Post date:** [May 22, 2023, 3:23pm UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/6 "2023-05-22T15:23:55Z")

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Why would you need to calculate the angles? You can simply set the length of the sides.

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**Author:** ![Eableson](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/eableson/32/10848_2.png) [@Eableson](https://discourse.shapr3d.com/u/Eableson)\
**Post date:** [May 22, 2023, 5:10pm UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/7 "2023-05-22T17:10:11Z")

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If only Drafting was still current curriculum 🙁 I learned all of this from helping my dad in the workshop.

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**Author:** ![DesertDave](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/desertdave/32/18343_2.png) [@DesertDave](https://discourse.shapr3d.com/u/DesertDave)\
**Post date:** [June 5, 2023, 2:00pm UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/8 "2023-06-05T14:00:25Z")

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Sorry for not replying sooner, but thank you for this. I’m ashamed I didn’t think of it myself and I really appreciated the video.

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**Author:** ![DesertDave](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/desertdave/32/18343_2.png) [@DesertDave](https://discourse.shapr3d.com/u/DesertDave)\
**Post date:** [June 5, 2023, 2:01pm UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/9 "2023-06-05T14:01:41Z")

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My high school had drafting tables left over from when they used to offer the class, stopping about 4 years before I entered (in 1982). I would have loved such a class.

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**Author:** ![NDS](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/nds/32/20986_2.png) [@NDS](https://discourse.shapr3d.com/u/NDS)\
**Post date:** [June 7, 2023, 3:43am UTC](https://discourse.shapr3d.com/t/how-do-i-draw-a-2d-triangle-with-fixed-side-lengths-angles-unknown/25925/10 "2023-06-07T03:43:39Z")

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Geometry class should work: triangle constructions.