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If the radius of a circle is reduced by 1 / 3, its area will be reduced by 25 square decimeters
If the radius of the circle is reduced by one third,
The radius is 2 / 3 of the original
The area is 4 / 9 of the original
The area has been reduced by 5 / 9
So the original area = 25 △ 5 / 9 = 45 square decimeters
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