A circle is divided into several equal parts to form an approximate parallelogram. The circumference is increased by 6cm. The original area of this circle is () square centimeter

The increased part of perimeter is the length of two radii, so the radius is 3 and the area is 3 times 3.14 = 28.26 square centimeter

Divide a circle into 16 parts on average, and then put it together into a parallelogram (as shown in the figure). The perimeter of the parallelogram is 41.4cm, and the area of the circle is______ Square centimeter

Let the radius of the circle be r cm. From the meaning of the question, we can get: 2 π R + 2R = 41.4, 2 × 3.14r + 2R = 41.4, 8.28r = 41.4, r = 5; s = π r2s = 3.14 × 52 = 78.5 (square cm); answer: the area of the circle is 78.5 square cm. So the answer is: 78.5

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