"The blouse is as big as the skirt."

Translation: A blusa é tão grande quanto a saia.

[josenino972]

Can "quanto" also be replaced by "como" in this case? Or is quanto the main word used for these types of comparisons?

[erudis]

It's grammatically correct, but in Brazil you'll probably hear "tão - quanto" a lot more.

[IsaacVasconcelos]

I don't think it's grammatically correct. As you said, it's a "tão - quanto" case, so if there is "tão", the "quanto" has to follow. It's, formally, a comparison rule.

[Alf-Sawman]

Thanks for the clarification - I wrote 'tão - como' and was deemed wrong by Duolingo. However, the suggested correct answer was just 'é grande como', i.e. the system suggests I skip the 'tão' rather than exchanging 'como' with 'quanto'.

[baldgymnastnurse]

Can anyone give an example where 'como' would be used in a comparative sentence as opposed to 'quanto'?

[Agfay]

if you speak european portugal, i presume...

[Alf-Sawman]

You could use 'como', I would claim, but it gives a slightly different meaning (nuances). "A blusa é grande como a saia" would be more like "The blouse is big, like the skirt" vs. "as big as" expressed by 'tão - quanto'. (But then again, the generic disclaimer: I'm not native, neither in PT nor in EN.)

[DaleWheatley]

A blusa é quantos grande tão a saia was marked as incorrect... correct?

[Alf-Sawman]

You are switching the order, it should be "A blusa é tão grande quanto..." (without 's' at the end) or "A blusa é grande como..."