In quadrilateral ABCD, ad ∥ BC, in order to determine whether ABCD is a parallelogram, the angle a + angle c = 180 degrees should be satisfied
Ad = BC should also be satisfied
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- 1. In the circle inscribed quadrilateral ABCD, AC and BD intersect at point E, and AE = CE, prove ad × AB = DC × BC
- 2. In the quadrilateral ABCD, AB is vertical to BC, DC is vertical to BC, P is a point on ad, PA = AB, PD = CD, then how many degrees is the angle BPC
- 3. AB is parallel to CD, ad is parallel to BC, angle a is equal to 3 angles B, find the degree of angle a, angle B, angle c and angle D
- 4. AB / / CD, ∠ DAB = ∠ BCD, try to explain AD / / CD
- 5. It is proved by counter proof that for any real number x, y, x ^ 2 + 2Y and Y ^ 2 + 2x, at least one of them is not less than - 1
- 6. It is proved that if x and y are positive real numbers and X + y > 2, at least one of 1 + XY < 2 or 1 + YX < 2 holds
- 7. (1) Given cos0 = - 1 / 2, find the value of sin0, tan0 (0 is the letter with a cross in the middle) (2) given tan0 = 2. Find sin0-2cos0 / 3cos0 + (1) Given cos0 = - 1 / 2, find the value of sin0 and tan0 (0 is the letter with a cross in the middle) (2) known tan0 = 2. Find the value of sin0-2cos0 / 3cos0 + 5sin0 (0 is explained above)
- 8. It is proved that AB is similar to ba
- 9. Let a and B be matrices of order n, ab = a + B. It is proved that: (1) A-E and B-E are invertible; (2) AB = ba
- 10. Given that the eigenvalues of matrix A of order 3 are 1,2,3, find | a * + A ^ 2 + 3E| Such as the title
- 11. In ▱ ABCD, it is known that ab = 2ad and M is the midpoint of ab. please confirm the position relationship between DM and MC and explain the reason
- 12. AC is the diagonal of parallelogram ABCD. Prove AB = CD BC = da
- 13. As shown in the figure, ▱ in ABCD, m, N, P and Q are the points on AB, BC, CD and Da respectively, and am = BN = CP = DQ
- 14. ▱ the circumference of ABCD is 36 & nbsp; cm, ab = 57bc, then the length of the longer side is () A. 15cmB. 7.5cmC. 21cmD. 10.5cm
- 15. How to arrange a sequence into B1 = A1, C1 = A2, D1 = A3, E1 = A4, B2 = A5, C2 = A6, D2 = A7, E2 = A8 B1 = A1, C1 = A2, D1 = A3, E1 = A4 can be used B2 = A5, what about this? ====I don't want to use all the devices, because there are too many operations 1000 data to operate 250 times five times, is 2500 times ====The best method is as follows: Input in B1: = indirect ("a" & row() * 4-3) Enter in C1: = indirect ("a" & row() * 4-2) Input in D1: = indirect ("a" & row() * 4-1) Enter in E1: = indirect ("a" & row() * 4) Select b1, C1, D1 and E1 to fill
- 16. Now there are four different integers a, B, C and D whose product ABCD = 25, then a + B + C + D =?
- 17. Given that ABCD is a rational number, the absolute value of a minus B is less than or equal to 9, the absolute value of C minus D is less than or equal to 16, and the absolute value of a minus B minus C plus D is equal to 25, find the absolute value of B minus a minus D minus C
- 18. It is known that ABCD is four different rational numbers, and the absolute value of 1 plus a is equal to the absolute value of 1 plus B, and the absolute value of 2 minus C is equal to 2 minus D How much is a plus B plus C plus D
- 19. What is prime a × prime B = 57, prime a + prime B = 57
- 20. Who are prime numbers in 57, 87, 89 and 49?