Learn Italian: Ho mangiato una bistecca grande.

In spoken Italian, the tense used for everyday completed actions is the passato prossimo, built with avere or essere plus the past participle. While it literally translates to I have eaten, it is the standard way to say I ate. The single-word simple past tense (passato remoto) is mostly reserved for written literature and history.

Why does mangiato end in -o instead of matching the feminine noun bistecca?

Because the helping verb is avere (used here as ho), the past participle mangiato stays in its default -o form. It doesn't change to match the noun after it. You generally only make the past participle agree with the noun if the helping verb is essere or if you use a direct object pronoun like la.

Since bistecca is a feminine noun ending in -a, why doesn't the adjective change to granda?

Not all adjectives change to -o or -a. The word grande belongs to a group of adjectives that end in -e in the singular, whether the noun they describe is masculine or feminine. It only changes to -i (like grandi) when the noun is plural.

Why is the adjective grande placed after bistecca instead of before it?