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The radius ratio of the two circles is 3:5. The total area of the two circles is 680 square centimeters. What is the area of the two circles? fast
If the radius ratio is 3:5, then the area ratio is 9:25
The area of the two circles is 9 (9 + 25) × 680
25÷(9+25)×680
If you know the area of a circle is 78.5, how to find the circumference, diameter and radius,
Square of radius = 78.5 △ 3.14 = 25
therefore
Radius = 5
Perimeter = 2 × 3.14 × 5 = 31.4
Diameter = 5 × 2 = 10
A circle with an area of 314 square decimeters has a radius of______ Decimeter, circumference is______ Decimeter
314 △ 3.14 = 100, 100 = 10 × 10, 3.14 × 10 × 2 = 62.8 (decimeter). A: its radius is 10 decimeters, and its circumference is 62.8 decimeters
The perimeter of the big circle is twice that of the small circle. The area of the small circle is 6 square decimeters. What is the area of the big circle
6 times 2 * 2 = 24
19: Can you give me the answer before 30: the area of a circle is 314 square centimeters, find the radius, diameter and perimeter
Radius = radical (314 △ 3.14) = 10 cm
Diameter = 10 × 2 = 20 cm
Perimeter = 20 × 3.14 = 62.8 cm
It is known that the area of a circle is 1256 square centimeters. What is its radius, diameter and perimeter?
Area of circle: S = π * r * r = 1256 (cm2)
So radius: r = 20 (CM)
Diameter: D = 2 * r = 40 (CM)
Perimeter: l = 2 * π * r = 126 (CM)
For football and basketball often all round the area, diameter and perimeter radius!
Please, there will be a lot of points!
The rules of football match concerning the ball used in the match are as follows:
The ball for competition shall be round, its shell shall be made of leather or other approved materials, and no materials that may harm athletes shall be used in its structure
The circumference of the ball shall not be more than 71 cm or less than 68 cm. The weight of the ball shall not be more than 453 g or less than 396 g at the beginning of the game. After inflation, the pressure shall be equal to 0.6-1.1 atmospheric pressure (at sea level), that is, 600-1100 g / cm '. In the game, the ball shall not be replaced without the permission of the referee
According to this calculation, the radius of the football should be between 10.8-11.3 cm
2、 Regional settings
Middle circle: a circle with 9.15m radius and service point as the center
Goal area: on the line 5.50M away from the inside of the goal at both ends of the playing field, a line 5.5m long and perpendicular to the end line is led to the playing field. One end of the line is connected with the goal, and the other end is connected with and parallel to the end line. These three lines are connected with the area within the end line. (end line is the line marking the width of the playing field.)
Penalty area: on the end line 16.5m away from the inside of the goal post at both ends of the competition field, draw a line 16.5m long and perpendicular to the end line. The other end points of the two lines are connected with each other and parallel to the end line. The three lines are the area surrounded by the end line
Free throw point: there is a clear mark at 11m from the midpoint of the two ends
Free throw arc: it is an arc outside the free throw area with the free throw point as the center and the radius of 9.15m
Corner area: take the intersection of the outer edge of the sideline and the end line as the center of the circle, take 1 m as the radius of the 1 / 4 arc in the field, it intersects with the sideline and the end line, and the area in this arc is the corner area
basketball court
The standard basketball court is a rectangular flat with a length of 28 meters and a width of 15 meters. The court must have an obvious boundary. There should be no obstacles within 2 meters of the boundary, and there should be a distance of at least 2 meters between the boundary and the audience, The boundary of the short side is called the end line. The horizontal line parallel to the end line connecting the middle points of the two sidelines is called the middle line. The middle line should extend 15 cm outside the sidelines on both sides. The circle drawn with the middle point of the middle line as the center and 1.8 m as the radius is called the middle circle. The free throw line is a straight line parallel to the end line, The free throw line and the two diagonal lines connecting the two ends of the free throw line are called the restricted zone (three second zone). The restricted zone plus the semicircle drawn outside the restricted zone with the midpoint of the free throw line as the center and the diameter of the free throw line as the diameter is called the free throw zone, The area outside the arched line at both ends of the court is the 3-point shooting area. All lines on the court must be very clear, and the width of the lines is 5cm. The measurement of the court, except that the sideline and the end line are calculated from the inner edge of the line, all lines in the court are calculated from the outer edge of the line
Basketball court facilities
1. Backboard: the two backboard should be made of transparent material, preferably reinforced safety glass, and its hardness is equivalent to the thickness of 3cm wood. The specification of the backboard is 1.80m wide, 1.05M vertical height, and its lower edge is at least 2.90M away from the floor. The surface of the backboard should be flat, and a rectangle with 59cm wide and 45cm high should be drawn from the outer line, The upper edge of the rectangular baseline must be connected with the upper end of the hoop
2. Basket: basket includes hoop and net. Hoop - made of solid iron, with inner diameter of at least 45 cm and at most 45.7 cm, and painted orange. Metal hoop with diameter of at least 1.6 cm and at most 2.0 cm. Net - should be white, hanging on the hoop, so that the ball can be slightly resisted after entering the basket. The net should have 12 meshes to hang on the hoop, with length of at least 40 cm, The maximum length shall not exceed 45 cm
3. Ball: the basketball must be a round body with orange color. The outer skin must be made of leather, rubber or synthetic material. The degree of air pressure in the ball should be measured from the bottom of the ball at a height of about 1.8 meters to the playing field. The rebound height should not be less than 1.2 meters or higher than 1.4 meters from the top of the ball
4. Timer: in order to display the time of the game, the match between the two sides and the number of fouls committed by the team, the timer should be installed in a place where everyone in the field can clearly see
5. 30 second timer: the 30 second timer shall be automatic, digital countdown, and display unit is second
6. Record sheet: the record sheet of all official matches held by the International Basketball Association shall be approved by the International Basketball Association
7. The number of fouls: it should be white with a minimum size of 20cm long and 10cm wide. In 2 × 20 minute competition system, the number is 1-5 (1-4 is black and 5 is red). In 4 × 12 minute competition system, the number is 1-6 (1-5 is black and 6 is red)
8. Team foul sign: the team foul sign should be red, at least 20cm wide and 35cm high, and placed on the record desk, so that everyone on the field can clearly see it
How to calculate the area, perimeter, radius and diameter of a circle
s=πr^2
C=2πr
r=1/2d
The area ratio of the big and small circles is 9; 1. The perimeter difference is 4 π cm. What is the sum of the areas of the two circles?
The area ratio of the two circles is 9; 1
So the diameter ratio is 3:1
The perimeter ratio is 3:1
The circumference of small circle is 4 π (3-1) = 2 π
Radius of small circle 2 π (2 π) = 1
The radius of the great circle is three
The sum of areas is 3x3x π + 1x1x π = 10 π square centimeter
(1) The area of a circle is 3.14 square centimeters. Find the radius, diameter and perimeter of the circle. (2) the perimeter of a circle is 78.5%
Meters to find his radius, diameter and area
A:
(1) The radius of the circle is r, the diameter is D, and the circumference is L
Then the area s = π R & # 178; = 3.14r & # 178; = 3.14
Radius r = 1cm
Diameter d = 2cm
Perimeter L = π d = 6.28cm
(2) The radius of the circle is r, the diameter is D, and the circumference is L
Then the perimeter L = π d = 3.14d = 78.5cm
Diameter d = 25cm
Radius r = 12.5cm
Area s = π R & # 178; = 3.14r & # 178; = 490.625cm & # 178;
RELATED INFORMATIONS
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