Su ke printing plate eighth grade first volume mathematics final examination paper 1. Fill in the blanks (2 points for each question, ***24 points)
The arithmetic square root of 1.9 is; The cube root of -27 is.
2. Point A (3, -4) is located in the fourth quadrant, and the distance from point A to the origin O is equal to.
3. If the average value of data 2, x, 4 and 8 is 4, then the mode of this set of data is; The median is.
4. It is known that point A (3, b) and point B (a, -2) are symmetrical about y axis, then A =；; b=。
5. If it is known that the image of the linear function intersects with X at point A (2 2,0), then k =；; The value of this function y increases with the increase of x (padding increases or decreases).
6. In the isosceles triangle △ABC,? A=4？ B. (1) What if? A is the vertex angle, then? c =； (2) What if? A is the bottom corner, then? C=。
7. The area of the diamond is 24cm2, the length of one diagonal line is 8cm, and the length of the other diagonal line is: the circumference of the diamond is.
8. According to statistics, 20 1 1 year? In the first phase, a scenic spot in our city received 89,740 tourists. Keeping this number to three significant figures can be expressed by scientific notation.
9. The analytical formula of the straight line passing through point P (0 0,5) and parallel to the straight line y=-3x+7 is.
10. As shown in the figure, in the isosceles trapezoid ABCD, AD∨BC, AB=AD=DC,? B=60？ , AE∑DC, if AE=4 cm, the circumference of trapezoidal ABCD is.
(DrawingNo. 10) (DrawingNo. 1 1)
1 1. As shown in the figure, in △AOB,? B=25？ , rotate clockwise around point o △AOB 50? Get delta a? OB？ , side a? b？
Intersect with the edge OB at point c (point a? Not on OB), then? Answer? The degree of CO is.
12. As shown in the figure, it is known that the area sum of squares 1 and No.4 is 5, and the area sum of squares A, B and C is 5.
Second, the choice (2 points for each question, *** 18 points)
13. The following statement is correct.
What is the square root of A.9? 3 b. What is the cube root of1? 1
C.=? 1d. The arithmetic square root of a number must be a positive number.
14. As shown in the figure, fold a square piece of paper diagonally once, then dig a round hole at each of the three corners of the triangle, and finally unfold the square piece of paper to get the pattern as follows.
15. The image of linear function fails.
A. first quadrant B. second quadrant C. third quadrant D. fourth quadrant
16. Under the following conditions, it cannot be determined that △ABC is a right triangle.
A. glycolic acid: glycolic acid = 3: 4: 5
C.？ A+？ B=？ C D？ A: Huh? b∴？ C=3∶4∶5
17. If the lengths of two sides of an isosceles triangle are 3 and 6 respectively, then the circumference of this triangle is
A.12 b.15 c.12 or15d.9.
18. Point, on a straight line, is related to size.
A.b.c.d is not sure.
19. As shown in the figure, in trapezoidal ABCD, AD∨BC, the middle line EF intersects BD at point O. If OE: of = 1: 4, then AD: BC is equal to.
1∶2 b . 1∶4 c . 1∶8d . 1∶ 16
(drawing 19) (drawing 20) (drawing 2 1)
20. As shown in the figure, points E, F, G and H are the midpoints of AD, BD, BC and CA in any quadrilateral ABCD. When the sides of quadrilateral ABCD meet the following conditions, quadrilateral EFGH is a diamond.
A.AB∨DC B . AC = BD C . AC D . AB = DC
2 1. As shown in the figure, known rectangular paper ABCD, point E is the midpoint of AB, and point G is a point on BC. BEG & gt60? Now fold the paper along the straight line EG, so that the point B falls on the point H on the paper, and connect AH. The number of equal angles is
A.4 B.3 C.2 D. 1
Third, answer questions:
22. (4 points for each small question, ***8 points) Calculation and evaluation.
(1) known: (x+5)2= 16, find x; (2) Calculation:
23. (8 points for this question) Operation and inquiry
(1) As shown in the figure, the coordinates of point A and point B are known as (0,0) and (4,0) respectively. Rotate △ABC 90 counterclockwise around point A? Get delta ab? c？ .
1 draw △AB? c？ ;
② point c? The coordinates of.
(2) As shown in the figure, in the plane rectangular coordinate system, the image of the function is the bisector of the first and third quadrants.
Experimental exploration: By observing the chart, it is easy to know that the coordinate of A (0 0,2) about the symmetrical point of a straight line is (2,0). Please mark the positions of the symmetrical points of B (5,3) and C (-2,5) about a straight line in the figure, and write down their coordinates:,;
It is found that the coordinates of the above three groups of points are observed by graphics,
You will find any point on the coordinate plane.
P(m, -n) is about the angular plane of the first and third quadrants.
The coordinates of the symmetrical point of the dividing line are:
24. (7 points in this question) In order to educate and guide the use of students' pocket money, a teacher spent a week investigating the pocket money of 50 students in the class and drew a statistical table and chart as shown in the figure.
Allowance amount (RMB) 5 10 15 20
Number of students (a) a 15 20 5
Please answer the following questions according to the information in the chart.
(1) Find the value of a;
(2) Find the mode, average and median of the pocket money of each of these 50 students for one week.
25. As shown in the figure, in △ABC, D is the point on BC and O is AD.
At the midpoint of, the parallel line with A as BC intersects the extension line of BO at point E, and then the four sides.
What is the shape of ABDE? State your reasons.
26. (6 points in this question) It is known: As shown in the figure, in the right-angle OABC, the edge OA,
OC is on the X axis and Y axis respectively, A (10/0,0) and C (0 0,6).
Point d is on the side of BC, and AD=AO.
(1) Try to explain OD bisection? CDA
(2) Find the coordinates of point D;
27. (7 points in this question) It is known: As shown in the figure, is the center of the O-side ABCD equally divided by BE? DBC, which intersects DC at point E, extends BC to point F, makes CF=CE, connects DF, and intersects the extension line of BE at.
G point, connecting OG
(1) Description: △ BCE △ DCF;
(2) 2) What is the positional relationship between OG and BF? Explain your conclusion;
28. (8 points in this question) It is known that, as shown in the figure, in the plane rectangular coordinate system xOy, a straight line
Intersect with the straight line at point A (-2,4).
(1) Find the analytical formula of the straight line;
(2) If a straight line intersects another straight line at point B,
And the abscissa of point B is -4. Find the analytical expressions of straight lines AB and △ABO.
The area of.
29. (8 points in this question) A communication company has introduced ① and ② two communication charging methods for users.
Yes, one of them has a monthly fee, and the other has no monthly fee. The functional relationship between the communication time x (minutes) and the fee y (yuan) of the two charging methods is as shown in the figure.
(1) The charging method with monthly fee is (fill in ① or ②).
The monthly fee is 100 yuan;
(2) Calculate y and independent variable by ① and ② charging methods respectively.
The functional relationship between x;
(3) Please give economic facts according to the communication time of users.
Hui's choice suggestion.
In the eighth grade, the first volume of the final examination paper of mathematics, Su Keban's answer 1, fill in the blanks (2 points for each question)
1、3; -3; 2, 4; 5 3、2; 3 4、-3; -2 5、- 1; Minus 6,30 o 80 o
7、6; 20 8、8.97? 104 9、y=-3x+5 10、20 1 1、75 o 12、 18
Second, choose
13、A 14、C 15、A 16、D 17、B 18、C 19、B 20、D 2 1、B
Three. 22.( 1) (2 points) (4 points, 1 is one)
(2) The original formula =4-2-3(3 points) =-1 (4 points)
23.( 1)① Omit (2 points) ② point C? (-2.5)(4 points)
(2)(2) ① As shown in the figure, (2 points) ②(-n, m) (4 points)
24.( 1) The total number of people is 50, so a = 50-15-5-20 =10 (1).
(2) The pocket money of 20 people this week is 15 yuan, which is the most frequent, so the pattern is15; (3 points) = 12. (5) The median is 12.5(7).
25. The quadrilateral ABCD is a parallelogram. (1) △ AOE △ DOB (3) gives AE=BD(4).
∫AE∨BD，？ The quadrilateral ABDE is a parallelogram. (6 points)
26.( 1) in the rectangular OABC, OA//BC? CDO=？ And then use AD=AO to get DOA( 1)? ADO=？ Direction of arrival (2 points)
? CDO=？ Addo (3 points)
(2) In Rt△ABD, BD2=AD2-AB2 BD=8(4 points) CD=2 (5 points) D (2 2,6) (6 points).
27.( 1) Because the quadrilateral ABCD is a square, BC=DC( 1 point). DCB=？ DCF=90？ (2 points), and CF=CE, then △ BCE △ DCF (3 points).
(2) (4 points) △ BCE △ DCF is known from (1), so? CDF=？ CBE, what else? CEB=？ What about DEG? DGE=？ BCE=90？ (5 points) because Be is equally divided again? DBC, so GF=GD. (6 points) and O squared the center of ABCD, then OG is the center line of △DBF, so. (7 points)
28. Solution: (1) substitute X =-2, Y = 4 to get 4=-2m, m=-2( 1), (2).
(2) Replace Y = 2x with x=-4, and Y =-8b (-4, -8) (3 points).
Because the straight line passes through a (-2,4) and b (-4,8).
So k=6, b= 16 y=6x+ 16, (5 points, find a value of k and b for 1 minute).
Let AB and X axis intersect at point C, at y=6x+ 16, let y=0, and x= (6 points) is obtained.
S△ABO= S△ACO +S△BCO= (8 points) (ladder division reference score)
29. Solution: (1) ① (1); 30(2 points)
(2) let Y have =k 1x+ b and Y have =k2x, and get (3 points) b=30(4 points) (5 points).
Therefore, the analytical formula is y = 0.1x+30; Y none = 0.2x 。
(3) If Y has =y has nothing, then 0.2x=0. 1x+30, and the solution is x = 300.
When x=300, y=60. (6 points)
Therefore, it can be seen from the figure that when the call time is less than 300 minutes, it is economical to choose the call mode ② (7 points); When the call time exceeds 300 minutes, it is more economical to choose the call mode ① (8 minutes).