Final answer:
The appropriate form of the verb estar to fill in the blank is estuvo.
Step-by-step explanation:
The appropriate form of the verb estar to fill in the blank in the question '¿Dónde está Beatriz ayer?' is estuvo. The verb estuvo is the past tense form of estar and is used to express actions or states that occurred in the past. In this case, the question is asking where Beatriz was yesterday, so the past tense form is used.
Learn more about Verb conjugation in Spanish