Question

What is the maximum number of points that can be placed on a circular disk of radius 1 metre (some of the points could be placed on the bounding circle of the disk) such that no two points are at a distance of less than 1 metre from each other?

A.
6
B.
9
C.
7
D.
8
E.
5

Accepted Answer

C. 1 point can be placed at the center. On the perimeter of radius 1, a regular hexagon of side length 1 can be formed with 6 vertices. Distance between adjacent perimeter points is 1, and distance from center to each perimeter point is 1. Total maximum points = $1 + 6 = 7$.

Maximum Points on a Disk

Explanation

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