a) Make a sketch.
One single small circle has the radius of 4 cm.
Its center is located at the distance 12-4 = 8 cm from the center O.
You easily get the right angled triangle with the hypotenuse of 8 cm and the leg of 4 cm.
Its acute angle is 30 degs; so one small circle blocks the central angle of 60 degs.
And EACH such circle blocks 60 degs.
So, 4 circles block 240 degs.
b) If 4 interior circles block the entire circumference, it implies that each small circle blocks the central angle of 90 degs.
Then it is easy to see that the distance from O to the center of each small circle is cm.
You can put this solution on YOUR website! This is a part of the Australian Mathematics competition
You are not allowed to CHEAT
please provide me with your name and school before or we must use IP address tracking to disqualify you and give you further consequences for attempting malpractice. You would rather be disqualified than suspended, for malpractice from your school. You are a disgrace!!!!!!!
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