Answer: 21.46%
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Explanation:
Let's find the area of one of the circles
A = pi*r^2
A = pi*10^2
A = 100pi
One circle is exactly 100pi square meters in area.
Four of the circles then combine to a total area of 4*100pi = 400pi square meters.
The distance along the bottom of the square is equal to two diameters, each diameter being 2r = 2*10 = 20 meters. So the distance along the bottom of the square is 2*20 = 40 meters. The square has an area of 40^2 = 1600 square meters.
The shaded region would therefore have an exact area of 1600-400pi square meters.
This approximates to 1600-400pi = 343.362938564082
Divide this over the area of the square to get the probability we want to find:
343.362938564082/1600 = 0.21460183660256
That's roughly 0.2146, which converts to 21.46%
