A.B. C. D。
2. With the following groups of line segments as edges, what can form a triangle is ().
A. 1 cm, 2 cm, 4 cm B.8 cm, 6 cm, 4 cm.
C. 12 cm, 5 cm, 6 cm D.2 cm, 3 cm, 6 cm
3. As shown in the figure, the straight line AB intersects the straight line CD at the point O, OE⊥AB, the vertical foot is O, EOD = 30, then BOC = ().
150， 140， 130， 120
(Figure 3) (Figure 4)
4. As shown in the figure, AB∨CD cannot be judged as () in the following situations.
A.∠3 =∠4 b .∠ 1 =∠5 c .∠ 1+∠4 = 180d .∠3 =∠5
5. The following proposition is incorrect ()
A. Two straight lines are parallel and have the same angle. B.the straight line between two points is the shortest. C. the vertex angles are equal. D. the vertical line segment is the shortest.
6. Among the following surveys, () is suitable for a comprehensive survey (census).
A. investigation on water quality of lijiang river. B. investigation on the quality of zongzi in the dragon boat festival market.
C. a survey of the weight of 50 students in a class. Safety investigation of fireworks and firecrackers.
7. On the number axis, the solution set of inequality group is correct ().
A B C D
8. In order to know the weight of 400 senior two students in a school, 50 students were selected for statistical analysis. In this question, it generally refers to ().
A.400b Selecting 50 students
C.C.400 Weight of 400 students D. Weight of 50 students.
9. In order to reward athletes who have achieved good results in the school sports meeting, a class spent 400 yuan money to buy two prizes, A and B ***30.
A, where each first prize is 16 yuan and each second prize is 12 yuan. How many do you want to buy for each of the two prizes? This problem
If we buy X A prizes and Y B prizes, the correct equation set is ().
A.x+y = 30 16x+ 12y = 400 b . x+y = 30 12x+ 16y = 400 c . 12x+ 16y = 30x+y = 400d . 16x+ 12y = 30x+y = 400
10. As shown in the figure, BD and CD are known to be the bisectors of ∠ABC and ∠ACE respectively. If ∠ A = 45, the degree of ∠D is ().
20th-22nd
(DrawingNo. 10)
Fill in the blanks (2 points for each small question, *** 14 points)
1 1. If the two sides of an isosceles triangle are 5cm and 6cm respectively, then the perimeter of the triangle is _ _ _ _ _ _ _ _.
12. As shown in the figure, move ABC to the right along the straight line AB to reach the position of BDE. If CAB=50, ABC = 100, CBE= degrees.
13. As shown in the figure, if AB∨CD, ∠ A = 60 and ∠ C = 25 are known, then ∠ E = _ _ _ _ degrees.
(DrawingNo. 12) (DrawingNo. 13)
14. If the sum of the inner angles of a polygon is three times the sum of the outer angles, the polygon is _ _ _ _ _ _.
15. If the point (m-4, 1-2m) is in the third quadrant, the range of m is.
16. China has implemented "no smoking" in public places since May, 20 1 1. In order to cooperate with the "no smoking" campaign, a school organized a knowledge contest of "Smoking is harmful to health" with 20 questions. Answer one question correctly and score 10.
17. As shown in the figure, AD is the center line of △ABC, BE is the center line of △ABD, and it is the high EF of BD on the △BED side.
If the area of △ABC is 40 and BC= 10, the length of EF is _ _ _ _ _ _ _.
Third, answer questions.
18. (6 points for this question) Solve equations (Figure 18)
19. (7 points in this question) Solve the inequality group and express the solution set on the number axis.
20. (7 points for this question) In order to understand the physical quality of the seventh-grade boys in a school, the physical education teacher immediately took some boys to do pull-ups, and made statistics on their achievements, drawing a statistical chart with incomplete figures as shown in Figure 1 and Figure 2.
(1) There are some boys in this sampling test.
(2) Please complete the statistical chart in Figure 2;
(3) If five or more pull-ups are specified as the physical fitness standard, how many of the 350 ninth-grade boys in this school are estimated to meet the physical fitness standard?
Figure 1 Figure 2
2 1. (7 points for this question) As shown in the figure, this is a partial sketch of a city. In order to determine the location of various buildings:
(1) Please establish a plane rectangular coordinate system with the train station as the origin.
(2) Write the coordinates of the market and the supermarket.
(3) Please regard the stadium, hotel and railway station as three points and connect them with line segments to get △ABC. Then, translate the triangle down by four unit lengths, draw the translated one and find its area.
22. (7 points in this question) As shown in Figure ABC, AD is high, AE and BF are angular bisectors, which intersect with points O, ∠ BAC = 50, ∠ C = 70, and find the degrees of ∠DAC and ∠BOA.
23. (7 points in this question) As shown in the figure, EF//AD is known, =. Proof: ∠ DGA+∠ BAC = 180.
24. (7 points in this question) A computer dealer plans to purchase a batch of computer cases and LCD monitors at the same time. If you buy 10 computer chassis and 8 LCD monitors, * * * needs 7000 yuan; If you buy two computer cases and five LCD monitors, you need 4 120 yuan. What is the purchase price of each computer case and LCD monitor?
25. (8 points in this question) A school organized 340 students to carry out long-distance investigation activities, with 70 pieces of luggage/KLOC-0, and planned to rent two types of cars * * * 10. It is understood that each car of A can carry up to 40 people and 0/6 pieces of luggage, and each car of B can carry up to 30 people and 20 pieces of luggage.
(1) Please help the school design all feasible car rental schemes;
(2) If the rent of a car is 2000 yuan per car and the rent of b car is 1800 yuan, which feasible scheme can save the rent?