The total area enclosed by the small circles is what fraction of the area enclosed by the larger circle?
Suppose AB, the diameter of the large circle, is 30. Then the diameter of each small circle (e.g., AC) is 10.
The area of the small circles totals 7 · 
(5)2 = 175.
The area of the large circle is (15)2 = 225.
| So we have | 175 |
= | 7 | . |
| 225 |
9 |