First, you can definitely choose the right one! (This question *** 10 is a small question, with 3 points for each question and 30 points for * * *).
1. The left view of the geometry shown on the right is ().
2. Among the following figures, the figure representing the shadows of two small trees under the sun at the same time may be ().
3. A couple who love sports gave their baby 12 months old three building blocks with the words "20", "08" and "Beijing" written on them. If the baby can spell "Beijing 2008" or "Beijing 2008", they will give the baby a reward. Assuming that the baby can arrange the building blocks horizontally and vertically, the probability that the baby can get a reward is
4. Xiaoming uses two bamboo sticks with the same length as the diagonal to make a quadrilateral kite, so the shape of the kite must be () A, rectangle B, square C and isosceles trapezoid D, which is uncertain.
5. The point with equal distance to each vertex of the triangle is the triangle ()
A, the intersection of three perpendicular bisector, the intersection of three heights.
C, the intersection point d of three angular bisectors and the intersection point of three center lines
6. The main reason for the stair or downhill shape of the cinema is ().
A. For the sake of beauty B. Reduce the blind area C. Increase the blind area D. Keep the blind area unchanged
7. The original price of each set of students' winter sportswear was 100 yuan, and then the price was reduced twice in a row. Now the price is 8 1 yuan, so the average percentage of each price reduction is ().
a、9% B、8.5% C、9.5% D、 10%
8. Given that the coordinate of one intersection point of the image with the proportional function y=k 1x(k 1≠0) and the image with the inverse function y=(k2≠0) is (-2,-1), the coordinate of the other intersection point is ().
a 、( 2， 1)B 、( 1，-2)C 、( 2， 1)D 、( 2，- 1)
9. If the distance between A and B is 60km, the function image between the time y (hours) and the speed x (km/h) when the car travels from A to B is roughly ().
10. On New Year's Day, students in the math interest group send each other New Year cards, and every two students send each other one. Xiao Ming counted, and the whole group * * * gave each other 90 New Year cards, so what is the number of math interest groups? Let the number of math interest groups be x, then the equation can be listed as ()
a、x(x- 1)=90 B、x(x- 1)=2×90 C、x(x- 1)=90÷2 D、x(x+ 1)=90
Second, can you fill it out quickly and accurately?
1 1. The solution of the equation x2-3x+2=0 is _ _ _ _ _ _ _ _.
12. If the point (2 1) is on a hyperbola, then the value of k is _ _ _ _ _ _ _ _.
13. Proposition "The diagonals of isosceles trapezoid are equal". Its inverse proposition is
14. Xiaohong, Xiao Fang and Xiaoming need to determine the order of playing games. They agreed to use the method of "hammer, scissors and cloth". What is the probability that all three people will play a round of cloth?
15. The area of the diamond is 24, and the shorter diagonal length is 6, so the circumference of the diamond is _ _ _ _.
16. The quadratic equation with one root is zero, so the value is
17. The base angle of an isosceles triangle is 15 and the waist length is 20 cm, so the area of this triangle is
18. Please write a quadratic equation with one root and another root.
19. As shown in the figure, the point A on the inverse proportion function image passes through A, and the axis AB⊥ is in B. If S△AOB=5, the inverse proportion resolution function is _ _ _ _ _ _ _.
20. As shown in the figure below, the square ABCD with a side length of 3 rotates clockwise around point C by 30? After that, the square EFCG is obtained, and EF intersects with AD at H point, so DH is
Third, answer questions:
2 1. Solve the equation
① ② (x-3)2=2(3-x)
22. As shown in the figure, in the quadrilateral ABCD, diagonal lines intersect at points O, E, F, G and H respectively.
Is the midpoint of AB, BD, BC and AC.
(1) Verification: the quadrilateral EFGH is a parallelogram;
(2) When the quadrilateral ABCD meets certain conditions, is the quadrilateral EFGH a diamond?
And prove your conclusion.
23. As shown below, under the street lamp, the shadow of a wall pier (represented by line AB) is BC and Xiaoming.
The shadow (represented by line segment DE) is EF, and there is a big tree at m, and its shadow is MN.
Try to determine the position of the street lamp (represented by point P) and draw a line segment representing the height of the big tree in the picture.
If Xiao Ming's eyes are approximately regarded as point D, try to draw a picture to analyze whether Xiao Ming can see trees.
24. Hongda Fruit Shopping Mall sells a high-grade fruit. Profit per kilogram 10 yuan, you can sell 500 kilograms every day. According to market research, if the purchase price remains unchanged, the daily sales volume will be reduced by 20 kilograms for every increase in the selling price of 1 yuan. Nowadays, shopping malls make a profit of 6000 yuan every day, and at the same time benefit customers. How much should the price per kilogram go up?
25. It is known that the images of linear function y= 2x-k and inverse proportional function intersect at two points A and B.. If the abscissa of intersection a is 3,
Find the value of k;
Find the coordinates of a and b;
Find the area of △AOB;
Test paper reference answer
The title number is 1 2345 6789 LO.
Answer 2, 1 2 diagonal lines are equal.
The trapezoid is an isosceles trapezoid 20-4 100 cm2. The answer is not unique.
Fill in the blanks (3 points for each small question, 30 points)
Second, multiple-choice questions (3 points for each small question, 30 points for * * *)
The title is11213141516171819 20.
Answer c a c d a b b a b a
Third, answer questions:
2 1.①x 1= ②x 1=3，x2= 1
22.( 1) as shown in the figure.
(2) The height of the tree is MN.
(3) The connection AD intersects with the tree MN, so the big tree is underestimated.
23, the answer is not unique, as long as the students do it right.
24.( 1) Prove that ∵E and F are the midpoint of AD and BD respectively, and G and H are the midpoint of BC and AC respectively.
∴ef∥ab,ef=ab； GH∑AB，GH =AB
∴EF∥GH, ef = GH∴ quadrilateral EFGH is a parallelogram.
(2) When AB=CD, the quadrilateral EFGH is a diamond.
Reason: ∫E and F are the midpoint of AD and BD respectively, and G and F are the midpoint of BC and AC respectively.
∴EF=AB，fg = CD÷ab = CD ∴ef=fg
∴ The parallelogram EFGH is a diamond.
25. solution: link EC.
∵EF⊥BC, EG⊥CD, ∴ quadrilateral EFCG is a rectangle. ∴FG=CE.
BD is the diagonal of the square ∴∠abe=∠cbe. ABCD.
And BE=BE, AB=CB, ∴△ABE≌△CBE.
∴AE=EC.∴AE=FG.
26. Solution: (1) Let the functional relationship between y and s be,
Substituting S = 4 and Y = 32 into the above formula, we get k=4×32= 128.
So the functional relationship between y and s
(2) When s= 1.6,
Therefore, when the thickness of noodles is 1.6mm2, the total length of noodles is 80m.
27. solution: suppose that the price per kilogram will increase by x yuan, according to the meaning of the question, it is
(10+x)(500-20x)=6000, the solution is x 1=5, x2= 10.
∵ Make customers benefit ∴x 1= 10.
A: The price per kilogram should be increased by 5 yuan.
28. Solution: (1) is given by x=3, 2× 3-k =, and the solution is k=4.
(2) When k = 4, the linear function is y = 2) k=4, and the inverse proportional function is
The 2x-4 solution gives x 1 = 3, x2 =-1∴ a (3,2) b (-1,-6).
(3) The coordinate of the intersection of straight line AB and X axis is (2,0).
∴S△AOB=×2×2+×2×6=8