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Explanation:
The area of the square is 12*12 = 144 square cm since each side is 12 cm long.
If we were to glue together all of those quarter-circle pieces, then we'd form a full circle of radius 3 cm. The area of that said circle is pi*r^2 = pi*3^2 = 9pi
The shaded area is therefore exactly 144-9pi square cm
Plug in pi = 3.14 to get the approximate value
144-9pi = 144-9*3.14 = 115.74