# 2.2 .3 .

A covered football field of rectangular shape with a length of $100 \mathrm{m}$ and a width of $80 \mathrm{m}$ is being designed, which must be illuminated by four spotlights, each hanging at some point on the ceiling. Each spotlight illuminates a circle, the radius of which is equal to the height at which the spotlight hangs. It is necessary to find the minimum possible ceiling height that meets the following conditions: every point on the football field is illuminated by at least one spotlight; the ceiling height must be a multiple of 0.1 m (for example, 19.2 m, 28 m, 33.9 m, etc.).
Answer: $32.1 \mathrm{m}$. 

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