The radius of this lake is 80 meters. S=2πr π is 3.142 * 3.41.80 = 502.4m2, and the radius of the island is 20 2 * 20 *. 3. 14= 125.6 m2. The main thing is that I don't know whether you are talking about the lake island area or the lake island area. The lake island covers an area of 502.4+ 125.6=628 square meters. The lake island covers an area of 502.4- 125.6=376.8 square meters.

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