de, del, de la Please explain

Question

Juana es la hermana de Juan Carlos.
El libro es de la tia Julia
Aquaesta el perro del abuelo

why del and de la.....why are the la and el in the bottom two sentences?

Have to go to work. check back tonight.

Thanks

Answer 1

Thank you both!

Answer 2

The definite articel for abuelo is -el. That is the reason and for tia is -la.
Del is combined form of de and el. de + el=del
when it comes to your first sentence ; since it is already a private name we don't use any definite articel.
I dont know if the answer was satisfactory.Adios.

Answer 3

I am sure that someone can give you a much better answer but, del is the combination of de and el. So, it is most common to see del or de la depending on the gender of the article. And, even though de el isn't wrong, it is hardly ever used. Much like I am not is hardly used and I'm not is much more common. With regards to why la and el are in the sentences has to do with tia and abuelo being, in essence, titles. When you are referring to someone by or with their 'title' you use el or la.