The perimeter of a square is equal to that of a circle. If the side length of a square is known to be 3.14 cm, then the radius of the circle is

The perimeter of a square is 4 * 3.14 = 12.56cm. According to the perimeter formula of a circle C = 2 π R, then r = C / 2 π = 12.56 / 2 * 3.14 = 2cm. Its area is s = π R & sup2; = 3.14 * 2 & sup2; = 12.56cm & sup2;

RELATED INFORMATIONS

1. In a square with a side length of 6cm, cut out the largest circle. How much smaller is the area of the circle than that of the square?
2. Cut the largest circle on a square iron sheet 12 cm long on one side, and the area to be cut is______ Square centimeter
3. 1. Cut out the largest circle in a square with a side length of 4 cm. The area of the circle is (12.56) square cm 2. The diameter of the outer circle is 8 decimeters, the radius of the inner circle is 2 decimeters, and the area of this circle is () square decimeters 3. The radius of a semicircle is 6 decimeters, and its circumference is (37.68) decimeters 4. A circle with a circumference of 28.26 meters, if its diameter expands to three times of the original, its area expands to () times
4. The area of a circle is 12.56 square centimeters. There is a square in the circle. Find the square area
5. There are two circles. The area of the big circle is 9 times that of the small circle. The circumference of the big circle is 12.56 cm more than that of the small circle. How many cm are the circumference of the big circle and the small circle? There are two circles. The area of the big circle is 9 times that of the small circle. The circumference of the big circle is 12.56 cm more than that of the small circle. How many cm are the circumference of the big circle and the small circle?
6. When the radius of a circle increases from 3cm to 5cm, the circumference increases by () cm
7. The radius of a circle is 5cm and the diameter is 5cm___ Cm, circumference is___ Cm, the area is___ cm2．
8. 1、 The radius of a circle is 5cm, its perimeter is () cm, and its area is () cm2
9. A garden with a radius of 3.5cm, what is its diameter, perimeter and area?
10. A circle, 5cm in diameter, how many cm in radius
11. A square with a side length of 16 cm, draw a circle, how many cm is the radius of the circle (), how many cm is the circumference of the circle ()
12. In a square with a circumference of 12 cm, draw a circle with the side length of the square as the diameter. How many cm is the circumference of the circle? Is that 9.42 cm?
13. The radius of a circle is π M. what is the area of the circle
14. 1. Known: radius of circle r = 2cm, calculate area of circle 2. Known: diameter of circle d = 6cm, calculate area of circle 3. Known: the circumference of the circle is 6.28cm, find the area of the circle 4. It is known that the arc length of 30 ° center angle is 1.57cm, and the area of the arc is calculated The radius of the big turntable in the amusement park is about 50 meters. How many square meters is the area of the circular surface produced by its rotation? How long is the route for tourists to take this big turntable to rotate for a week? The first question is to ask () and the second question is to ask ()
15. When the radius of a circle increases from 4cm to 6cm, how many square centimeters does the area of the circle increase?
16. It is known that the sum of the radii of the two circles is 6cm, the perimeter of the big circle is 25.12cm, the area of the small circle is () and there are two big and small circles, the radius of the big circle is 6cm, and the diameter of the small circle is 4cm The difference between the area of these two circles is very urgent
17. The diameter of circle a is 4cm, the radius of circle B is 6cm, and the area ratio of circle a and circle B is () A 4mm precision instrument parts, drawing on the map has 4cm, the scale is () The () and () of a circle are in direct proportion How many times does it take to transport 2700 tons X is proportional to y () 1. X + y = 30 2. Y = 2 / 3 x 3. Xy = 2 / 3
18. When the radius of a circle is three times the original, the area of the circle is () times larger
19. If the radius of a circle increases by 10%, the area of the circle increases by ()%
20. When the radius of a circle increases from 6 cm to 9 cm, the area of the circle increases () A. 9 π square centimeter B. 45 square centimeter C. 45 π square centimeter