1. It is known that the base angle of the trapezoid is 45 degrees, the height of the trapezoid is equal to the upper base, and the length of the lower ground is 9, then the waist length of the trapezoid is () A. 3 B.5 C.3 times root 2 D.2 times root 3 2. In the trapezoidal ABCD, the length of the waist BC is (), when the two base angles AB = 14cm, CD = 6cm, a = 30 ° and B = 60 ° respectively A.8cm B.6cm C.4cm D.3cm

1 C
The height of a trapezoid that is isosceles and 3 times the base
2 C
Using Pythagorean theorem

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1. For a linear function: y = KX + B, there are the following statements: (1) the larger the value of K is, the faster the straight line rises; (2) the intercept B is the distance that the straight line cuts on the Y axis; (3) when k > 0, y increases with the increase of X, K
2. Mathematics in grade two of junior high school 1. The opposite sides of two similar polygons are 3 cm and 4.5 cm respectively. If the sum of their areas is 130 square cm, then the area of the smaller polygon is 1________ square centimetre. 2. Given △ ABC ∽ a'b'c ', and ab: a'B' = 2:3, s △ ABC + s △ a'b'c '= 75, then s △ a'b'c'=______ .
3. 1. If x ^ 2 + 3x-1 = 0, then x-3 / 3x ^ 2-6x ^ (x + 2 - 5 / X-2)=________ . 2. If M / A ^ 2-B ^ 2 - 2ab-b ^ 2 / A ^ 2-B ^ 2 = A-B / A + B, then M=_______ .
4. (1) In the quadratic equation of one variable: the square of X + BX + C = 0, if the coefficients B and C can be taken in 1,2,3,4,5,6, then the number of equations with real number solutions is [?] (2) If x satisfies the square of X - 3x + 1 = 0, then the value of X + (1 / x) is [?]
5. 1. If a = - 0.3 ^ 2, B = - 3 ^ - 2, C = (- 1 / 3) ^ - 2, d = (- 1 / 3) ^ 2, then the size relationship of a, B, C, D is________ . 2. If 6 / 7 = 6 (5a + 2) / 7 (5a + 2), then the value range of a is_______ .
6. 60：40=（）/（） 0.5：0.4=（）/（） If the product of two inner terms of a proportion is the smallest prime, one outer term is 3, and the other outer term should be () Judgment: Because 3x = 7Y, so x: y = 7:3 ()
7. Poplar is 2 / 9 of willow, and poplar is a fraction of willow A road has been built 4 / 15 of its total length, and what has been built is a fraction of what has not been built A shoe store sold shoes of various sizes last week (table below) Size 21.5 22.5 23 23.5 24 Quantity 10 24 56 34 12 8 In your opinion, this shoe store should buy more shoes of size () The following is a book read by several students. 558 9 10 13 30 40 (median / mode / average) is suitable to represent the general level of the book
8. Help me out 10 simple fill in the blanks about the knowledge I have learned in the first volume of grade 6. Write out the answers
9. 1. The lift is a () phenomenon 2. On clocks, the rotation of the hour hand and minute hand is () phenomenon It's the second volume of grade 6 published by Chenguang Publishing House of Yunnan publishing group company It's better to have an answer on pages 54 to 57,
10. ）. The sum of all divisors is () The decimal point of a decimal, move one place to the right, 5.4 larger than the original, the original number is () A natural number divided by 2, 3, 4, 5, the result is more than 1, such a number has (), the smallest is () The letter expression of the relationship between fraction, division and ratio is () The number of a is three eighths of the number of B. the ratio of a to B is (). The number of a is three eighths more than that of B. the ratio of a to B is () () divide by () = 3 / 4 = () = (): () = () 12 / 4 = ()% The side length of a square is ()% of the circumference This year's per capita income is 12% higher than that of last year, so this year's per capita income is ()% This year's per capita income is 12% higher than last year's, so this year's per capita income is ()% of last year's
11. 1. The value of the arithmetic square root-2 of estimate 27 is () A. It's between 1 and 2 B. It's between two and three C. It's between three and four D. It's between four and five 2. There are five propositions 1 / zero is the smallest real number 2 / points on the number axis cannot represent all real numbers 3. Irrational number is the number with root sign The cube root of - 1 / 27 is ± 1 / 3 5. There are two square roots of a positive number, which are opposite to each other The correct ones are: () A. 1 B.2 C.3 D.4
12. Just one question. Explain the reason There is a parallelogram with a length of 6 on one side. How long are his two diagonals/ A. 4 and 6 B. 4 and 8 C. 2 and 6 D. 6 and 8
13. As shown in the figure, ab = AC, be ⊥ AC at point E, CF ⊥ AB at point F, be and CF intersect at point D, then ① △ Abe ≌ △ ACF; ② △ BDF ≌ △ CDE; ③ point D is on the bisector of ∠ BAC A. ①B. ②C. ①②D. ①②③
14. If 102x = 25, then 10-x equals () A. 15B. −15C. 150D. 1625
15. Mathematics problem in grade two of junior high school The result of simplifying M & sup2; - (m-2) - m-2 is A：m²/（m-2） B：（m²-2）/（m-2） C：4/（m-2） D：4 Please help me! Thank you! Wrong number, simplified m²/（m-2）-m-2
16. It is known that in the triangle ABC, BD and CE are the heights of the sides AC and ab respectively, and M is the midpoint of BC. If we connect de and take the midpoint o of De, what is the positional relationship between Mo and de
17. Looking for five geometry problems in mathematics volume 1 of grade 2 of junior high school There should be a graph and a solution. The teacher asked us to collect 5 questions. We should use the solution of grade two
18. 5 + the decimal part of root 7 is a, 11 minus the decimal part of root 7 is B, find the value of a plus B and a minus B
19. Second grade mathematics multiple choice question! Online wait for answer! Xiaohua prepared three wooden sticks to make a right triangle frame. Xiaoying accidentally cut off one of them by a third. Xiaohua can still make a right triangle as long as she takes the other two wooden sticks A. Cut off one-third B. cut off two-thirds C. both of the above can be done D. do not need to change Please explain the reason! Thank you! What's more, is the cut-off one third a proportion or a quantity??
20. 1. When x > 1 is simplification ------------------- Square of (x + 1 / x) - 4 2. The two adjacent sides of the parallelogram are 3 and 5. The length of the two line segments divided by an acute angle bisector is 3. It is known that the length of four sides of a trapezoid is 1, 2, 3 and 4 respectively, then the area of the trapezoid is