Seventh grade mathematics
First, choose carefully (there are 5 small questions in this question, each with 3 points, full score 15 points, and only one of the four options given in each of the following questions is correct. )
1. represents the solution set of one of the following inequality groups on the number axis, as shown in the figure, then this inequality group is ().
A.B.
C.D.
2. Among the following four propositions, the correct one is ()
A. the same angle is equal. B. Equal angles are diagonal.
C. adjacent complementary angles are equal. D.A, b and c are straight lines, a‖b, b‖c, and then a ‖ c.
3. The following plane graphics can't be inlaid into a plane pattern is ().
A. arbitrary triangle B. arbitrary quadrangle C. regular pentagon D. regular hexagon
On May 3, 20091day, the slogan of World No Tobacco Day was "Quit smoking for an hour, and hundreds of millions of people walk healthily". In order to know how many adults smoke in this area, Xiaohua study group randomly investigated 100 adults, and the result was 15 adults smoking. Regarding this question about data collection and description, the following statement is true ().
A. The survey method is census B. Only 85 adults in this area don't smoke.
C the sample is 15 adults who smoke. D. About 15% of adults in this area smoke.
5. Choose three pieces of wood with lengths of 9, 6, 5 and 3 to form a triangle. * * * There are () options.
A.4 B.3 C.2 D. 1
Second, fill in patiently (there are 5 small questions in this question, 3 points for each small question, full score 15)
6. inequality 2x-1>; The solution set of 5 is.
7. As shown in the figure, in △ABC, ∠ A = 80 and ∠ B = 60, then ∠ 1 =.
8. If the sum of the internal angles of a polygon is equal to 360 degrees, then it is a polygon.
9. The point (2,-1) moves to the left by 3 unit lengths, and the point is in the fourth quadrant.
10. Rule exploration: Connect the midpoints of three triangles in the graph (1) to get graph (2), then connect the midpoints of three triangles in the middle of the graph to get graph (3), and so on, then there is a triangle in the nth graph.
Third, answer with your heart (this big question has a small question of 10, and the score is ***70. The answer requires a written explanation of the proof process or calculation steps)
1 1, (6 points in this question) Solve equations.
12, (6 points in this question) solve the inequality group, and indicate that its solution set is on the number axis.
13, (6 points in this question) If, what about X and Y?
14, (6 points in this question) As shown in the figure, in the plane rectangular coordinate system, the coordinates of point A are (2,4) and the coordinates of point B are (3,0). Translate △AOB by 2 units along the direction of ray OB, where the corresponding points of A, O and B are D, E and F respectively.
(1) Please draw the translated △ def;
⑵ Find the swept area of line segment OA during translation.
15, (6 points in this question) as shown in the figure, AB‖DC,,,
(1) The number of times to find ∠D;
(2) the degree of calculation;
(3) Whether DA‖CB can be obtained, please explain the reasons.
16, (6 points in this question) There are 40 students in Class A and Class B of Grade 7 in a middle school in Tianhe. The results of a math exam are as follows: (each group of scores contains the minimum value, but does not contain the maximum value). Answer the questions according to the information provided in the following figure and table:
(1) Please complete three statistical charts (tables);
(2) What is the central angle of the sector occupied by "90~ 100" in the sector statistical chart?
(3) What do you think are the characteristics of these three charts?
17, (6 points in this question) The shape of a part is as shown in the figure, and according to the regulations, A = 90? ，∠ C=25？ ，∠B=25？ , check the measured BCD = 150? , judge that the part is unqualified, and explain the reason of the unqualified part with the knowledge of triangle.
18, (9 points in this question) Calculate the price of each kitten and puppy according to the information given.
Buy a * * * to 70 yuan,
Buy a 50 yuan.
19, (9 points for this question) 20 questions in a math contest. Get 10 for each question correctly, and deduct 5 points for wrong or no answer. Answer a few questions wrong or not at most, and the score can be no less than 82 points.
20. (Question 10) In order to celebrate the arrival of the Beijing Olympic Games, the garden department decided to use the existing 3,490 pots of A-type flowers and 2,950 pots of B-type flowers, with 50 gardening shapes A and B, and put them on both sides of Jinshan Avenue. It is known that 80 pots of A-type flowers and 40 pots of B-type flowers are needed to match 50 pots of A-type flowers and B-type flowers.
(1) The extracurricular activity group of Class 7 (1) in a school undertook the design of this gardening modeling collocation scheme and put forward the problems that meet the requirements.
How many matching schemes are there? Please help design it.
(2) If the cost of matching an A-shape is 800 yuan and the cost of matching a B-shape is 960 yuan, try to say.
Which scheme had the lowest cost in Ming Dynasty (1)? How much is the minimum?