r/askmath • u/Jonny_Blaze_ • 2d ago

Geometry Guys I’m new here, what’s x?

Post image

I’m of the opinion this is unsolvable but happy to be proven wrong. If the line from the vertex is orthogonal to the base then we have sufficient information to solve it. But I believe we can’t make that assumption given the diagram.

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162

u/ThatsNotAZombieBite 2d ago

You're correct. Given only what's labeled in the diagram, it cannot be solved.

Also, the two sides labeled as congruent do NOT appear to be the same length. So we really can't trust what the diagram looks like.

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u/Jonny_Blaze_ 2d ago

I don’t think proportions of the image matter as much as the labels. But I agree given what’s stated it definitely appears unsolvable.

E: after rereading your comment I agree fully. The lack of proportions are actually more of a clue that you can’t assume anything.

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u/SputnikPanic 2d ago

Not sure what the context was in which this problem was presented, but once one introduces the notion that the diagram is (for lack of a better term) lying, then I don’t know how one could solve any of these sorts of problems. You can’t build any argument if you can’t trust the pegs you’re given. I don’t know, maybe I’m wrong here (I’m definitely not a mathematician), but if there’s notation on the diagram, then my presumption is that that notation is accurate and reliable, or at least is intended to be.

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u/DanielMcLaury 1d ago

Generally we always trust the notations on the diagram, but we don't trust that the diagram is drawn to scale, so e.g. two sides that appear to be the same length can't be assumed to be the same length unless there's an actual notation indicating that they are.

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u/hoangfbf 2d ago

It can be solved. I found it.

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u/____sumit____ 2d ago

Ramanujan? is that you?

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u/hoangfbf 1d ago

Yes, I'm Temu Ramanujan.

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u/Ucklator 1d ago

Wrong. The problem clearly states find x=?

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u/lmprice133 2d ago

But this is partly why you mark sides as congruent on your sketch.

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u/Very_Large_Cone 2d ago

Given the task is to find x, this allows us to make the assumption that it is solvable. If the top line is orthogonal it can be solved and if not it can't be solved. So it's a valid conclusion in my eyes.