Writing proofs — advanced questions

Can it be that what I'm asked to prove doesn't make sense?

Sometimes a question is non-standard, and it was adapted for the system differently from the original wording. Go back to the original question (Original question image) to understand how the two wordings differ.

Why is the theorem I want on the list but grey, so I can't choose it?

It means the theorem is blocked for this question. Usually that's because the point of the question is to prove this theorem, or theorems based directly on it, but there are other reasons too. If it looks like a mistake, you can write to us.

Why can't I add the auxiliary construction I want?

Auxiliary constructions are set in advance for each question, and you can't add constructions that weren't set. Write to us if you have an idea for a proof that needs an auxiliary construction the question doesn't have.

How do I add units of measurement?

At the moment the only unit you can write is degrees (for angles).