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UKMT Junior Kangaroo, 2015

Geometry Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

The diagram shows five circles of the same radius touching each other. A square is drawn so that its vertices are at the centres of the four outer circles. What is the ratio of the area of the shaded parts of the circles to the area of the unshaded parts of the circles?

(A) $1:3$ (B) $1:4$ (C) $2:5$ (D) $2:3$ (E) $5:4$

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