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... swer:

Assuming that the radius of the small circle is r, and the circumference as ?.

= 2πr

The question asks for the area between radius 1 and 3, so we’ll call it ‘S’.

Therefore, the answer is 8π.

Teacher's Comment:

Well answered. This is a standard question for area.

Yoshii Akihisa's Answer:

Teacher's Comment:

It's been a while since I felt my veins popping.

Tsuchiya Kouta's Answer:

Te ...

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