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The circumference of a circle is fixed, and its ratio is inversely proportional to its diameter. Right or wrong? The judgment of midterm exam, I hit X
No. Pi is a fixed value
What is the ratio of the Pi of a circle with a diameter of five centimeters to that of a circle with a diameter of one meter
The ratio of the Pi of a circle with a diameter of five centimeters to that of a circle with a diameter of one meter is 1:1
True or false: the ratio of circumference to diameter ()
No, PI is perimeter divided by diameter,
The ratio of diameter to perimeter is one in π
True or false: because Pi is the quotient of circumference length divided by diameter, the Pi of large circle is larger than that of small circle
No. Pi is constant: 3.1415926535798972
The circumference of a circle is () times of its diameter, and its circumference = () / ()
π. The ratio of circumference is usually 355 / 113
Calculation of ancient pi How do they calculate the area of N
The ratio of circumference to diameter of a circle is a constant, which is called PI. It is usually expressed by the Greek letter π. In 1706, Jones, an Englishman, first used π to represent PI. His symbol was not immediately adopted. Later, Euler advocated it and gradually spread it. Now π has become a special symbol of PI, the study of π, To a certain extent, it reflects the level of mathematics in this area or era
In ancient times, in fact, the value of π = 3 has been used for a long time, such as Babylon, India and China. By the 2nd century B.C., Chinese Zhoubi Suan Jing had already recorded the first day of the third week. Mathematicians in the Eastern Han Dynasty changed the value of π to (ca
It is the first time to use the upper and lower bounds to determine the approximate value in science. The first time to use the correct method to calculate the value of π was Liu Hui in Wei and Jin Dynasties, In 263 ad, he initiated the method of approximating the circle area by the area of the inscribed regular polygon of a circle, and the value of π was calculated to be 3.14. This method is called cyclotomy in China. It was not until 1200 years later that a similar method was found in the West. In order to commemorate Liu Hui's contribution, later generations called 3.14 Hui rate
In 460 ad, Zu Chongzhi of the Southern Dynasty used Liu Hui's cyclotomy to calculate the value of π to 3.1415926, which was the first time in the world to calculate the PI with seven decimal places. Zu Chongzhi also found two fractions: 22 / 7 and 355 / 113, which greatly simplified the calculation by replacing π with fractions, which was more than 1000 years earlier than that in the West
In 1596, the Dutch mathematician Rudolf broke the Pi of Zuchongzhi. He pushed π to the 15th decimal place and finally to the 35th place. In order to commemorate his achievement, people engraved on the tombstone after his death in 1610: 3.14159265358979323846264338327950288, which is also called "Rudolph number"
The greater the circumference of a circle, the greater the PI () Fill in the brackets with "√" × "!
Wrong! Pi is a fixed constant 3.14159265358
Make the largest circle in a square. The area of the circle accounts for π of the square area 4．______ .
Let the radius of the circle be r, then the side length of the square is 2R,
Then π R2 △ (2R × 2R),
=πr2÷4r2，
= Pi
4；
So the answer is: √
Draw the largest circle in a square. The ratio of the circumference of the circle to the circumference of the square is () ratio (). The area of the circle is a fraction of the square, and the area of the remaining part is a fraction of the area of the square
Draw the largest circle in a square. The ratio of the circumference of the circle to the circumference of the square is π: 4
The area of a circle is square: 157 parts of 200
The area of the rest is the area of a square: 43 times 200
Draw the largest circle in a square with a circumference of 32 decimeters. The area of the circle is ()
32 △ 4 = 8 decimeters
8 △ 2 = 4 decimeters
The area of a circle is that of a square: 3.14 × 4 ^ (8 × 8) = 78.5%
RELATED INFORMATIONS
- 1. Draw the largest circle in a square with a circumference of 32 decimeters. What is the area of the circle?
- 2. The circumference of a circle is the same as that of a square. The side length of the square is 6.28 cm. What is the area of the circle?
- 3. The diameter of a circle is 5 meters. What is its circumference? The ratio of circumference is 3
- 4. The position relation between circle x ^ 2 + y ^ 2-4x + 2Y + 4 = 0 and circle x ^ 2 + y ^ 2 + 2x-6y-26 = 0
- 5. Given the circle C1: x square + y square + 2x + 6y + 9 = 0 and circle C2: x square + y square - 6x + 2Y + 1 = 0, find the common tangent equation of circle C1 and circle C2
- 6. The linear equation of chord length 8 passing through point a (- 1,10) and cut by circle x2 + y2-4x-2y-20 = 0 is______ .
- 7. If two circles x2 + y2-10x-10y = 0 and X2 + y2-6x + 2y-40 = 0 intersect at two points, the equation of the line where their common chord is located is______ .
- 8. Find a point in the ellipse C: x ^ 2 + 4Y ^ 2 = 16. Find the equation of the line where the chord is located with a point a (1, - 1) in the ellipse x * 2 + 4Y * 2 = 16 as the midpoint
- 9. If the chord ab of the circle x ^ 2, y ^ 2 = 20 is made through the point P (2, - 3), and P bisects AB, then the equation of the line where the chord AB is located is
- 10. The straight line kx-y + 1 = 0 and the circle x? 2 + y? 2 = 1 intersect a and B, and find the locus of the midpoint of chord ab
- 11. PI 1 to 100
- 12. If the perimeter of an equilateral triangle is equal to that of a circle, then their area ratio is equal to
- 13. An equilateral triangle has a circumference of 2.4 decimeters and a height of 0.6 decimeters. Its area is () decimeters
- 14. It is known that the radius of circumscribed circle of regular hexagon is 2, and the area of regular hexagon is?
- 15. Formula for calculating the area of regular hexagon?
- 16. As shown in the figure, ∠ AOC: ∠ cod: ∠ BOD = 2:3:4, and a.o.b is on a straight line, OE.OF Divide ∠ AOC and ∠ BOD equally, og bisect ∠ EOF, and calculate ∠ GOF
- 17. Given the triangle ABC, the angle c is a right angle, and Ca = CB, D is the midpoint of CB, e is a point on AB, and AE = 2be, it is proved that ad is perpendicular to 2EB Using the scalar product of a plane vector, Should be AE = 2EB, verify that ad is perpendicular to CE
- 18. AB is the chord of circle O, AE, arc = BF, arc radius OE, of intersect a, B, C, D respectively, which indicates that OCD is isosceles triangle
- 19. 1. The vertical bisector of line AB is Mn, if point P is on Mn and PA = 10cm, then Pb=________ 2. On the triangle ABC, ab = AC, BC = 2, angle BAC = 30 degrees, the vertical bisectors on its three sides intersect at point O, then OA=———— 3. In the triangle ABC, ab = 7, AC = 5, ad is the center line of side BC, then the value range of ad is______
- 20. As shown in the figure, in the hexagon ABCDEF, AF ∥ CD, ab ∥ ed, ∠ a = 140 °, B = 100 °, e = 90 °. Calculate the degrees of ∠ C, ∠ D and ∠ F