Create triangle given 2 corner angle and 1 side length

My first steps with Sketchup

How to draw a triangle, with 2 corner angles, and one side length is known?

Online web version

Draw the known edge, then use the protractor tool to draw guides at the two angles. Finish by drawing edges from the ends of the start edge to where the guides intersect.


Moved to the proper category.

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Or just copy/rotate that first edge around one endpoint over one angle and then copy/rotate that first edge around its other endpoint over the second angle. Then either delete the unwanted edges exceeding the new intersection or move both free endpoints towards the virtual intersection of both new edges

It all may sound complicated but is rather easy and will be a nice exercise in stretching edges along their direction using inferencing.


There are three possible similar triangles depending on which of the sides the known length applies to.

Correct, from basic geometry. For there to be a unique answer I assumed the angles were at the ends of the given side. If that’s not the case we need another constraint.

thx for all reply, I was using the protractor on the wrong axis so there was no intersection.
It would be nice to have a pop-up where you can edit the properties like in this (sorry it is in dutch)

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I know but that would have been a long story, to include all options. It doesn’t make it any more difficult to create the desired triangle without (or if one insists with) guides.

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