In english "accurate" and "precise" have distinct and complementary meanings (especially in science) -- are there equivalent distinctions in portuguese? [Accurate means factually correct - Precise means measured with great fidelity - something can be accurate, but not precise; precise but not accurate; both; or neither]
Yes, when we talk in science terms:
accurate - exato (accuracy - exatidão)
precise - preciso (precision - precisão)
although it's easy to confuse them in colloquial speech.
Report it when you see that with the other button, don't post in here please
Could one also say : "the size is... A)" just right" ? B) "correct"? C) "precise"?
Yes. "Precise" is a synonym of "accurate", so it works as a direct translation of "preciso". "just right" and "correct" are equivalent expressions, they're not direct translations (so there's a possibility of Duolingo not accepting them) but they work.
Are they really synonyms? I don't think so. One can be precise but inaccurate, or inaccurate but precise. If your age is exactly 35 years and 112 days, and it is reported as being 33 years and 45 days, this would be inaccurate but precise. If I said that I have around $10000, and I really have $10135, this would be accurate but imprecise.
I agree that the mathematical terms "precise" and "accurate" have different meanings, but in colloquial speaking people often confuse them, so if anyone told me "the size (e.g. of this t-shirt) is precise" I would assume they meant accurate.
I've just consulted the dictionary, with which I will not argue. You are correct, and I retract my statement.