Correctness Check in the Geometry Tool

I’m trying to make an activity where students’ can check if their geometric constructions are correct. For example, here is a screen I made where students can check if they corrected constructed an equilateral triangle:

The problem with this approach is that students need to drag points to the triangle they already constructed to check. Even if their construction is incorrect, as long as they have an equilateral triangle with the right side length it will be marked correct.

Does anyone have any idea of how to do this without dragging points?

You can check the construction step by step by using the variable ‘construction’:
https://teacher.desmos.com/activitybuilder/custom/67f6dd8d32f18e9c5554833a

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I knew there was something with construction, but am not familiar enough. I’d suggest maybe including a segment count as well, so the check doesn’t pop up just for the point.

{construction.segment.count >= 2}

Edit: Here I added in a segment check and a polygon check

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Yes, we can check that if we want the student to draw the triangle …

Hello everyone! Thank you so much for your feedback. I wanted it to be marked correct for students no matter how much they “explored” along the way. So they could make a series of “incorrect” constructions, but once they arrive at the equilateral triangle I would mark them correct. Here is my (possibly final) screen, with an added animation and a notice for students to use the polygon tool instead of the segment tool:

This looks really great, and has given me a couple of ideas for an activity!

@Guzman_Tierno - can you remember where the construction. notation/functionality is documented? When I first saw this post, I vaguely remembered that you could refer to construction objects in such a manner, but I couldn’t remember how and no amount of searching through the documentation provided me with the answer. But I was aware of it, so I have obviously read it somewhere…

I think that the documentation about the “construction” object is sparse and incomplete.
I myself proceed by trial and error …

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I also don’t recall where I saw it. This document is on the support.desmos.com help site, but there’s no reference to construction.

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I remember these two posts:
https://cl.desmos.com/t/how-to-get-the-list-of-vectors-of-the-construction/7389

https://cl.desmos.com/t/cl-newsletter-october-2023-the-new-geometry-component/5484

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Thank you! That must have been where I came across it originally.

I guess this is still considered ‘rough’ but it would be good to see this documented fully in the future.

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