Question regarding adjectives

Question regarding adjectives
 

Hi.

Please could someone explain to me why lo is used in the following sentence and not la.

Hay que ver LO guapa que es esa mujer.

Thank you for any help in advance. Much appreciated.

We use the neuter article "lo" to name the abstract quality referred by an adjective as if it was a noun. The adjective is used in its neuter form -the masculine is also the neuter form- unless the adjective also affects a real noun, then it has to coordinate with that noun.

neuter / masculine / femenine

Lo correcto es portarse bien.
Lo mejor es enemigo de lo bueno.
No puedo creer lo grande que está el niño.
No puedo creer lo grande que está la niña.
No puedo creer lo hermosa que está la niña.

Guapa is an adjective. But in your example it has been changed into a noun. To make an adjective a noun, the neuter article lo is used. Only the neuter article can be used this way.

Thank you both for your help. It is much appreciated.