As shown in the figure, in the diamond ABCD, ∠ ADC = 120 °, then BD: AC equals () A. 3：2B. 3：3C. 1：2D. 3：1

It can be seen from the question that ∠ ADO = 12 ∠ ADC = 60 °. Cot ∠ ADO = cot60 ° = do: Ao = BD: AC = 3:3

RELATED INFORMATIONS

1. The children in the big class of kindergarten made 32 flowers, among which the red flower was three times as much as the yellow flower. How much did the children make the red flower and the yellow flower
2. The perimeter of the rectangle is 19.4 meters. The length is 0.8 meters less than twice the width. How many meters are the length and width of the rectangle?
3. It takes 26 seconds for a train to pass the 396 meter bridge and 18 seconds to pass the 252 meter tunnel. How long is the train's body?
4. Find the following periodic functions 1. Y = sin3x / 4, X ∈ R 2. Y = cos4x, X ∈ R
5. Find the period of the following functions: (1) y = sin23x, X ∈ R; (2) y = 12cos4x, X ∈ R
6. The function with period 2 is () A. y=2cos2πx-1B. y=sin2πx+cosπxC. y=tan（π2x+π3）D. y=sinπxcosπx
7. Finding the minimum positive period of function {process} FX=sin{2x+PI/6}+sin{2x-pi/6}+cos2x
8. If the sum of the minimum positive periods of function y = sin ω X and function y = Tan ω x (ω > 0) is π, then ω=______ ．
9. The minimum positive period of the function y = 2sin2x is______ ．
10. What are the steps to prove that a function is periodic
11. How to prove the limit of n-th root of n is 1 by definition
12. In the quadrilateral ABCD, ad ∥ BC, ad = 24cm, BC = 26cm, the moving point P starts from point a and moves to point d at the speed of 1cm / s along the edge of AD, and the moving point Q starts from point C and moves to point B at the speed of 3cm / S along the edge of CB. P and Q start from a and C at the same time. When one point reaches the end point, the other point stops moving with it. Let the motion time be T seconds, what are the values of T respectively, then the quadrilateral PQCD and the quadrilateral pqcb are parallelograms?
13. Write correctly
14. The top and bottom of a right angled trapezoid is 3cm. If you extend its top and bottom by 5cm, it will become a square. The area of this trapezoid is () square%
15. One eighth (x-1) ^ 5 = A0 + a1x + a2x ^ 2 + +a5x^5 Find the A0 power of 3, A1 power of 27, A2 power of 3, A3 power of 27, A4 power of 3, A5 power of 27 There's 1 / 8 in front of us. That's why we can't count... Depressed~
16. If a commodity is sold at a 10% discount, it will make a profit of 20 yuan. If it is sold at a 70% discount, it will lose 10 yuan Yuan, then the purchase price and price of the commodity are
17. The more the better, the good can add points As long as the ordinary fraction or decimal calculation and application, do not judge the choice, application to write out the process
18. A washing machine now sells for 204 kg, which is 21% cheaper than the original price. How much is the original price? Use the equation. Thank you
19. 1. A cuboid, 4 decimeters long, 0.4 decimeters more than wide, the same height and width, its volume is * * cubic decimeters 2. The 6060 bricks, 20 cm long, 10 cm wide and 5 cm high, are neatly stacked together. The volume of this pile of bricks is * * M & sup3
20. The original price of a kind of TV set is 2500 yuan, and the sales promotion in the market is 1 / 5. After the activity, the price is increased by 1 / 5. How much is the current price of this kind of TV set?