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Prove that we can cover a region with 8 disks

Source:

September 29, 2010

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Problem Statement

(GDR 5)

Given a ring

G

in the plane bounded by two concentric circles with radii

R

and

\frac{R}{2}

, prove that we can cover this region with

8

disks of radius

\frac{2R}{5}

. (A region is covered if each of its points is inside or on the border of some disk.)