Una/un altitude

Question

Isn’t it correct to use either un altitud as well as una altitud because even though altitud is feminine, it starts with a stressed ‘a’?

John O'Leary · Accepted Answer

Hola Marc, I
 
I think the article of choice would be the feminine “una” following the guideline given in the lesson, whereby the emphasis is not on the first syllable; it is in fact on the final one “u.’
 Saludos John

Paolo - · Answer

The stressed syllable is the final -tudSo: una altitud

Inma Sánchez · Answer

Hola Marc
Yes, as John and Paolo rightly said, you need the stress on the first syllable to apply the masculine article: un
un águila, un arma, un arpa...
but not un altitud as the stress is on the last syllable, therefore, una altitud.
Saludos
Inma