For a ring, the radius of the inner circle is 3cm, the radius of the outer circle is 5cm, and the area of the ring is () square cm

sixteen

RELATED INFORMATIONS

1. The radius of the outer circle of a ring is 7cm, and the radius of the inner circle is 5cm?
2. The radius of a ring is 5cm, the width of the ring is 1cm, and how many square centimeters is the area of the ring?
3. The radius of the outer circle of a ring is 5cm longer than that of the inner circle, and the radius of the inner circle is 3cm. What is the area of the ring?
4. A circular ring, the diameter of the outer circle is 5cm, the radius of the inner circle is 3cm, how many square meters is its area?
5. If the radius of a circle is a centimeter and 2: a = A: 3, the area of the circle is () square centimeter A. 23 π B. 6 π C. 6D
6. If the radius of a circle is a centimeter and 2: a = A: 3, the area of the circle is () square centimeter A2 / 3 * 3.14 B6 * 3.14 C cannot be calculated
7. The radius of the circle has increased from 4 decimeters to 6 centimeters, and the area of the circle has increased by () square centimeters a, 6b, 20c, 20c
8. The radius of a circle is 2. What's the circumference and area of the circle? One more question The mass ratio of chocolate to milk is 2:9 {1} If you have 400 grams of chocolate, how many grams do you need
9. The radius of a circle is 6cm, and the circumference of the semicircle is () times?
10. For two circles with radius of 4cm and 6cm respectively, the perimeter ratio of small circle and large circle is (), and the area ratio is ()
11. The diameter of the small circle is 5cm, the radius of the big circle is 5cm, the perimeter ratio of the big circle and the small circle is (), and the area ratio is () Write down the formula
12. The radius of a small circle is 3cm, the radius of a large circle is 4.5cm. What is the simplest integer ratio of the circumference of a small circle to a large circle
13. The radius of a small circle is 3cm, and that of a large circle is 5cm. The simplest integer ratio of the area of a large circle to that of a small circle is______ ．
14. If the radius of the big circle is twice that of the small circle, and the area of the big circle is 12 square centimeters more than that of the small circle, then the area of the small circle is () A. 12 square centimeter B. 4 square centimeter C. 6 square centimeter D. 8 square centimeter
15. The sum of the circumference of the two circles is 78.5cm. The radius ratio of the big circle to the small circle is 3:2. What is the area of the big circle
16. The radius of a circle is equal to the side length of a square. The area of a square is 3 square decimeters. The area of this circle is 3 square decimeters
17. The side length of a square is equal to the radius of a circle, and the area of a square is 5 square decimeters (hint: a = R, the square of a = R, the square of a)
18. The radius of a circle is equal to the side length of a square. Given that the area of a square is 3 square decimeters, how many square decimeters is the area of the circle?
19. According to the requirements: as shown in the figure, the square area is 18dm2, find the area of the circle
20. Put the circle together into an approximate rectangle. The length of the rectangle is 6.28 decimeters. The area of the circle is______ Square centimeter, perimeter is______ Decimeter