The circumference of a circle is 12.56 cm, and its radius is______ Cm. If the radius is doubled, the area will increase______ Square centimeter

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• 1. The radius of a semicircle is 6cm. The area of the semicircle is (56.52) (I already know the area) square centimeter. What is the circumference? It is the circumference Expression
• 2. After cutting a circular piece of paper, put it together into an approximate rectangle with the width equal to the radius and the area unchanged. The perimeter of the rectangle is 16.56 cm. What is the area of the cut circular piece of paper in square cm?
• 3. If the circumference of a round lid is 56.52 cm, the area of the lid is______ Square centimeter
• 4. There is a circular fountain in the park, with a circumference of 31.4 meters. What is the area of the fountain?
• 5. There is a circular fountain in the park, with a circumference of 31.4 meters. What is the area of the fountain?
• 6. There is a circular fountain in the park, with a circumference of 31.4 meters. What is the area of the fountain?
• 7. There is a circular cistern on a piece of green space. Its perimeter is 31.4. How many square meters does it cover? The area of the circular cistern is 15% of the total area of this green space. What is the total area of this green space
• 8. There is a circular fountain in the park, with a circumference of 31.4 meters. What is the area of the fountain?
• 9. Build a 1-meter-wide circular road around a 94.2-meter-long circular pool. What is the area of this road
• 10. For a round pool, a 1-meter-wide path should be paved around it. How many square meters is the area of the path?
• 11. The sum of the diameter, perimeter and radius of a circle is 18.56 cm. The diameter of the circle is () cm and the area is () square cm Come back quickly! Come back before 9:00 tonight
• 12. Draw the largest circle in a square with a circumference of 48 cm. What is the circumference of the circle? How to analyze it
• 13. Draw the largest circle in a square. The circumference of the circle is 4.3cm shorter than that of the square. The circumference of the circle is () cm We have to hand it in tomorrow,
• 14. Draw the largest circle in the positive and negative shape with a circumference of 24 decimeters. What is the circumference of the circle In 1997, an orange tree at Jiaxiang road home in Shandong county produced an orange. The perimeter of the cross section of the orange is 85CM. What is its radius?
• 15. As shown in the figure, the shadow part accounts for 1 / 5 of the area of the big circle and 3 / 7 of the area of the small circle. Q: the ratio of the area of the big circle to the area of the small circle
• 16. As shown in the figure, the area of the shadow part is 18% of the area of the big circle and 38% of the area of the small circle. If the area of the shadow part is 15 square centimeters, find the total area of this figure
• 17. As shown in the figure, the area of the shadow part is 18% of the area of the big circle and 38% of the area of the small circle. If the area of the shadow part is 15 square centimeters, find the total area of this figure
• 18. Known shadow area is 20 square decimeters, ring area
• 19. There are two circles, big and small. The area difference between them is 62.8 square decimeters, and the radius of the big circle is 1.5 times that of the small circle. What are the areas of the two circles? know Big circle radius: small circle radius = 1.5:1 = 3:2 How to find the area?
• 20. There are two circles, big and small. The area difference between them is 62.8 square decimeters, and the radius of the big circle is 1.5 times that of the small circle. Then, what are the areas of the two circles?