Final answer:
Plural demonstrative adjectives modify the noun 'shoes' in the sentence 'How much do these shoes cost?'
Step-by-step explanation:
The type of adjective used to modify 'shoes' in the sentence 'How much do these shoes cost?' is a plural demonstrative adjective. In this sentence, the word 'these' is modifying the noun 'shoes' and indicating that the shoes are in proximity to the speaker and listener.
Learn more about Plural demonstrative adjectives in English sentences