Using a piece of square paper with a side length of 2 decimeters, cut a circle as large as possible. The area of the circle is () A. 3.14 square decimeters B. 12.56 square decimeters C. 6.28 square decimeters D. 24.92 square decimeters

Using a piece of square paper with a side length of 2 decimeters, cut a circle as large as possible. The area of the circle is () A. 3.14 square decimeters B. 12.56 square decimeters C. 6.28 square decimeters D. 24.92 square decimeters

3.14 × (22) 2 = 3.14 (square decimeter). Answer: the area of this circle is 3.14 square decimeter

The radius of the largest circle drawn in a square is () of the side length. If the side length of the square is 5cm, the area of the circle is ()

Half 3.14 * 2.5 square

Cut out the largest circle on a square cardboard with a side length of 10 cm. The area of this circle is () cm, and the remaining corner area is () cm

∵ is the largest circle in a square with a side length of 10 cm
∴C=a=10
S circle = square of π (10 △ 2) = 78.5 square centimeter
S positive residual corner = 10 × 10-78.5 = 21.5
THE END

Cut a circle with the largest area from a square cardboard with a side length of 20 cm. What is the area of the circle subtracted? What is the remaining area

The area of the minus circle is 100 π square centimeters
The remaining area is 400-100 π