In ricreazione, Marta usa il compasso per fare un cerchio sul quaderno della sua amica.

In ricreazione is a common set expression meaning at recess / during break in a school context. Italian often uses in + noun without an article in fixed time expressions like this.

• in ricreazione = at recess
• durante la ricreazione = during recess

Both are possible, but in ricreazione sounds very natural and compact here. Nella ricreazione is much less likely in this context.

Usa is the third-person singular present indicative of usare.

It matches Marta:

• io uso
• tu usi
• lui/lei usa

Italian uses the simple present in many cases where English might use either:

• Marta uses the compass...
• Marta is using the compass...

Without more context, the Italian present can describe a habitual action, a general statement, or an action happening in a vivid present-time narration.

Here il compasso means the drawing compass used in geometry to make circles.

That is a helpful false-friend point for English speakers:

• English compass can mean the navigation instrument or the drawing tool
• Italian compasso can also mean both, but in this sentence it clearly means the geometry tool

Because of per fare un cerchio, the school-geometry meaning is the natural one.

Here per + infinitive expresses purpose: in order to do something.

So:

• usa il compasso per fare un cerchio
• she uses the compass to make/draw a circle

This is a very common Italian structure:

• Studio per imparare = I study to learn
• Vado al supermercato per comprare il pane = I go to the supermarket to buy bread

So per fare means to make / in order to make.

Both can work, but fare un cerchio is very natural in everyday Italian.

Italian uses fare very broadly, often more broadly than English uses make/do. In a school or geometry context, fare un cerchio can mean make/draw a circle.

You could also say:

• Marta usa il compasso per disegnare un cerchio

That sounds a bit more explicitly like draw a circle, but the original sentence is completely normal.

Sul is a contraction of su + il.

• su = on
• il quaderno = the notebook
• su il quaderno becomes sul quaderno

This kind of contraction is very common in Italian with prepositions and definite articles:

• a + il = al
• di + il = del
• in + il = nel
• su + il = sul

So sul quaderno means on the notebook.

Because amica is not a close family term, Italian normally uses the definite article before the possessive.

So:

• la sua amica = her friend
• del quaderno della sua amica = of her friend’s notebook

Here della is di + la:

• di = of
• la sua amica = her friend
• della sua amica = of her friend

Italian often omits the article with singular family members:

• mia madre
• tuo fratello

But with amica, the article stays:

• la sua amica

The possessive sua agrees with the thing possessed, not with the owner.

Here the possessed noun is amica, which is:

• feminine
• singular

So the possessive must also be:

• feminine singular → sua

Compare:

• il suo amico = her/his friend
• la sua amica = her/his friend
• i suoi amici = her/his friends
• le sue amiche = her/his friends

So sua is feminine singular because amica is feminine singular.

In this sentence, the most natural interpretation is Marta’s friend, yes.

Grammatically, suo/sua can mean his, her, or even its depending on context. Italian does not mark the possessor’s gender in the possessive form. So sua amica literally just means his/her friend.

However, because Marta is the subject and no other person has been introduced, readers will normally understand:

• della sua amica = of her friend, meaning Marta’s friend

If context needed to remove ambiguity, Italian could rephrase it more explicitly.

Italian chooses quaderno della sua amica to make the owner explicit: the notebook belongs to her friend.

If you said:

• sul suo quaderno

that could be ambiguous, because suo might refer to Marta or to another female person depending on context.

Using della sua amica avoids that possible confusion and clearly ties the notebook to the friend.

Cerchio is the normal word for a circle in the geometric or visual sense.

• un cerchio = a circle

Circolo usually means a club, association, or sometimes a circular movement/group, not the shape you draw with a compass.

So with compasso and quaderno, cerchio is exactly the right word.

The word order is very normal for Italian.

• In ricreazione sets the time
• Marta is the subject
• usa is the verb
• il compasso is the direct object
• per fare un cerchio explains purpose
• sul quaderno della sua amica says where the circle is made

Italian word order is often similar to English, but it is usually a bit more flexible. This sentence follows a clear, natural order and does not sound unusual.