C. Two straight lines are parallel and have the same angle. d .∫≈ 1 =∠2，∠ 2 = ∠ 3，∴∠ 1 = ∠ 3。
4, three straight lines on the plane at least () intersect.
A.3 B.2 C. 1 D.0
5. The number of triangles that can be formed with three of the four line segments with lengths of 3cm, 5cm, 7cm and 10cm as sides is ().
a， 1 b，2 c，3 d，4
45
O
y
x
D
60
C
6. It is known that a triangle has two equal sides, one side is 3 and the other side is 5, so the circumference of the triangle is ().
A, 8 B, 1 1 C, 13 D, 1 1 or 13.
7. It is known that the radius of a circle centered on O is 3, if
If point C is marked as (3,45), point D should be marked as ().
A.(3,60)
B.( 120,3)
C.(60,3)
D.(3, 120)
8. If the outer angle of a triangle is equal to its adjacent inner angle.
Equal to 2 times the inner angle that is not adjacent to it.
4 times, then this triangle must be ()
A, acute triangle b, right triangle
C, obtuse triangle D, equilateral triangle
9, a vertex of the pentagon can be used as () diagonal.
A. 1
10, the following shapes of floor tiles with the same pattern cannot be embedded in the plane ()
A. regular triangle B. rectangle C. regular octagon D. regular hexagon
1 1. It is known that if the coordinate of point A is (a2, a2+ 1), then point A is at ().
A. In the first quadrant B. In the first quadrant or on the X axis.
C. On the Y axis D. On the first quadrant or Y axis.
12, the binary linear equation in the following equation is ()
a . xy = 1 b . x = y c . 2x+3y d . 3x+2y = 3x
13, it is known that an algebraic expression in which x is () contains y.
a . x = 10+b . y =- 15 c . x = 5+d . y =- 15
14. When axis A is known as AB//x/X, the coordinates of point A are (2, -3) and that of point B is ().
a2 B- 3
C.- 1 d is uncertain.
15, the line segment CD is translated from the line segment AB. The corresponding point of point A (-1, 4)
north
south
B
A
C
C (4 4,7), the coordinate of point B (-4,-1) corresponding to point D is ().
A(2，9) B(5，3) C( 1，2) D(-9，-4)
Two. Fill in the blanks (***30 points)
1, the sum of the outer angles of the dodecagon is _ _ _ _ _ _ _ _ _
As we all know, as shown in Figure B, it is located at 40 degrees southwest of A..
In the direction, c is in a.
From south to east 15 direction,
2
1
A
B
C
D
C is 80 northeast of b,
Then ∠ACB= ()
A
C
B
D
3. It is known that straight lines AB and CD are
Cut with a straight line L, ∠ 1 = ∠ 2 = 85,
Then the isoseismic degree of ∠ 1 is
4. It is known that point A on the Y axis satisfies AO=2, then the coordinates of point A are
5. Rt△ABC, ∠ BAC = 90 is known.
A
B
D
C
E
If AD⊥BC is in D, then this number is equal (Figure 5).
The acute angle * * * is right.
6. As we all know, AD⊥BC is located in D,
Then there is an advertisement in the picture.
A tall triangle.
7. Except one internal angle, the sum of all internal angles of an N-polygon is 1680 degrees.
So the number of sides of this polygon is, and the inner angle is degrees. (Figure 6)
8. It is known that (3m- 1) X2N+ 1+9 = 0 is a linear equation about X, then the conditions that M and N should meet are M and n =.
9. After the master worker finishes the door frame, in order to prevent deformation, two diagonal battens are often attached, as shown in the figure.
(that is, AB and CD in Figure 4), the mathematical reason for this is.
10, the proposition "complementary angles of the same angle are equal" is written in the form of "if" ... and then ... "
If so.
Third, solve the equation (10)
( 1) (2)
A
C
B
D
E
Fourth, think carefully and do it patiently.
1, (6 points) It is known that AE bisects the outer angle of △ABC, AE//BC,
Try to judge the relationship between ∠B and ∠C, and explain the reasons.
2.(7 points) It is known that △ABC, ray BE and CF bisect ∠ABC and ∠ACB, and BE and CF intersect at point O.
(1) Verification: ∠ BOC = 90+∠ A.
B
————
E
————
C
————
O
————
F
————
A
————
(2) If the condition "CF bisects ∠ACB" is changed to "CF bisects ∠ACB adjacent outer corners", other conditions remain unchanged. Is the conclusion in (1) still valid? If it is established, explain the reasons; If not, please find out the relationship between ∠BOC and ∠A and prove it.
3.( 10) It is known that △ABC, A(2a, b-3), B (-2, 4),
C (- 1, 3), shift △ABC downward by 6 units to get △ A1b1,and then parallel it to the right by 5 units to get △A2B2C2. If the coordinate of A2 is (b-2, A- 1).
(1) Find the values of a and b.
(2) Draw △ABC in rectangular coordinate system and translate to get △A 1B 1C 1 and △A2B2C2.
(3) Find the graphic area formed by the swept part during the translation from △ABC to △A2B2C2.
(Write the results directly, without giving reasons)
4.(6 points) It is known that the rectangular ABCD as shown in the figure is folded to the positions of D 1 and C 1 along EF.
If ∠ c 1fe = 1 15, find ∠AED 1.
A
————
B
————
D
————
C
————
E
————
D 1————
F
————
C 1————
5. (6 points for this question) In a polygon with equal internal angles, the internal angle is 4 times that of the external angle. Find the degree of each inner angle of this polygon and the number of sides of this polygon.
The seventh grade mathematics midterm exam answers:
1. 1, C 2, D 3, B 4, D 5, B 6, D 7, D 8, B 9, C 10, c1,d.
12、B 13、A 14、B 15、C
2, 1, 360 2, 85 3, 95 4, (0,2) (0,2) 5,26,67, 12 120.
8, m≠ 1/3 n=0 9, triangle stability 10, (omitted)
Three. 1，x=5，y=7 2，x =-4，y= 12。
Fourth, think carefully and do it patiently.
1,∠B =∠C-2 '
Reasoning -6'
2, 1) Proof-3'
(2)BOC =∠A-4
Reasoning -7'
3. Equations -2'
Solution:-4'
(2) Drawing -7'
(3)24 - 10′
4. Find ∠ d 1ef = 65 or ∠ BEF = 65-4'
Found ∠ AED 1 = 50-6'.
Solution: Let every inner angle of this polygon be x degrees, and all outer angles are degrees.
So every inner angle of this polygon is 144, and every outer angle is 36;
∴36n=360
n= 10
So this polygon is a 10 polygon. (6 points)
The reciprocal of 1 and a is.
2. If it is similar, then mn=.
3. There are three red balls, two yellow balls and 1 white ball in a bag (each ball is the same except the color).
You have the best chance to touch the _ _ _ _ _ _ _ ball.
4. Integer whose absolute value is greater than-and less than 1 is.
In three consecutive odd numbers, n is the largest odd number, so the sum of these three numbers is.
6. According to the 24-point algorithm, there are four numbers of 3, 4, -6, 10, and each number is only added, subtracted, multiplied and divided once, and the result is equal to 24, and the formula is = 24.
7. In the same plane, there are two positional relationships between two straight lines: and.
8. As shown in the figure on the right, it is known that ∠AOB is a right angle, ∠AOC is three times that of ∠COB, then ∠COB is.
9. If |x-y+ 1|+(y+5)2=0, then xy=.
Figure 7
Aortic second sound
A 1
B2
C2
C 1
D 1
B 1
D2
10. As shown in Figure 7, cut a cube with a plane, and the parallel lines in the section obtained are.
Second, multiple-choice questions (18 points)
1 1, which of the following figures is the surface expansion diagram of a cube ()
A B C D
12, the following statement is true ()
A, the distance between two points is the line segment between two points;
B, in the same plane, there is one and only one straight line parallel to the known straight line;
C, in the same plane, there is one and only one straight line perpendicular to the known straight line;
D Two lines perpendicular to the same line are also perpendicular.
13, the distance that the earth transits around the sun every hour is about1.1×105km, and the distance that the earth rotates in one day (within 24 hours) is about () by scientific notation.
A.0.264× 107 km B.2.64× 106 km
c . 26.4× 105km d . 264× 104km。
14, lines a, b, c, a‖b, a‖c, then the relationship between line b and line c is ().
A, intersection b, parallel c, vertical d, uncertainty
15, the denominator in the equation is an integer, and the result should be ().
a、B、0
c、D、0
16, rotate once along the dotted line in the figure 1, and the enclosed geometry in the following geometry is ().
A B C D diagram 1
Three. Calculation problem: (6 points)
17. Observe the following equation and answer the questions: ; ; …
(1) Fill in the blanks: = (n is a positive integer)
⑵ Calculation:++…+=.
Five, simplified evaluation (5 points)
18, (-3x2-4y)-(2x2-5y+6)+(x2-5y-1) where x =-3 and y =- 1.
Six, solve the equation (4 points for each small question, ***8 points)
19.4x-3(20-x)=6x-7(9-x) 20。 - = 1-
Seven, column equation to solve application problems (12 points)
2 1. Xiaoli's father deposited a two-year time deposit with an annual interest rate of 2.25% the year before last. After the expiration of this year, after deducting 20% interest as interest tax, the interest just bought Xiaoli a calculator worth 36 yuan. How much did Xiaoli's father save the year before last?
22. Hongyuan Shopping Mall originally planned to sell two commodities, A and B, at the price of 1500 yuan. After adjusting the price, A raised the price by 20% and B lowered the price by 30%. Actually, the transaction was made with 1600 yuan. What is the actual selling price of A's goods?
Eight, solve the problem (2 1 minute)
23. Known line segment AB=6 cm, point C is the midpoint of AB and point D is the midpoint of AC. Find the length of line segment BD.
A
B
C
D
24. Investigate the TV types of 400 households in a civilized district, make the survey results into a fan-shaped statistical chart (as shown in the figure), and answer the following questions according to the information provided by the statistical chart:
1. How many families have color TV sets?
2. What is the central angle of the sector representing the proportion of black and white TV sets in the picture?
25. A school organizes students to visit the Science and Technology Museum, which is 6 kilometers away from the school. Xiaohua is going to take a taxi to the science and technology museum at the school gate because she can't get on the school bus. There are two types of taxi charges, as shown in the following table:
Class A mileage fee (yuan) Class B mileage fee (yuan)
3 km or less (including 3 km) 7.00 6.00
More than 3 kilometers, each additional 0 kilometers 1.60 1.40.
(1) Let the taxi mileage be x kilometers (x≥3, x is a positive integer), and write two kinds of total charges (expressed by an algebraic expression containing x) respectively.
(2) Xiaohua only has 1 1 yuan. Is it enough for him to take a taxi to the science and technology museum? Please explain the reason.
15 Respondents: TTTPP 3-Jianghu rookie level 4 2009-5-117:14.
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Other answers *** 4
What is the average sum of 1+2+3+4+ 100?
Respondent: Zhang Zexi 1997- Beginner in Jianghu Level 2 2009-4- 19 2 1:39.
1. Equation 2007x+2007a+2008b (a and B are rational numbers, B >；; 0) has a positive integer solution, and a×b is ().
Negative numbers .. (b) non-negative numbers ... positive numbers ... zero. ..
2. An athlete from Party A and an athlete from Party B are practicing long-distance running on the circular track. Player A is faster than player B. If they start from the same starting point in opposite directions at the same time, they will meet every 25 seconds. Now, they are heading in the same direction from the same starting point at the same time. Athlete A caught up with Athlete B in 15 minutes and ran 13 laps more than Athlete B. At this time, Athlete B ran.
Please write down the process. .....
Answer:
2007x+2007a+2008b=0
2007a=-(2007x+2008b) Because there is a positive integer solution.
So x>0, b>0, so 2007x+2008b >; 0, then -(2007x+2008b) < 0,
2007a & lt0
a & lt0。
So ab < 0
Answer.
Because athlete A caught up with athlete B in 15 minutes and ran 13 laps more than athlete B,
So A runs 13/ 15 laps per minute.
Because we start from the same starting point in opposite directions at the same time, we meet every 25 seconds.
So every 25 seconds, two people run 1 lap.
Within 25 seconds, A ran more laps than B (1315)/(60/25) =13/36.
In this way, B ran (1- 13/36)/2=23/72 laps in 25 seconds.
So 15 minutes, B * * ran15 * (60/25) * (23/72) =11.5 laps.
Not enough, and typing is too slow ~
Respondent: sxwa 304320- Juren Level 4 2009-4-25 19:33
1. If positive integers x and y satisfy 2004x= 15y, then the minimum value of x+y is _ _ _
2004 and 15 have a common divisor of 3.
2004x= 15y, that is, 668x=5y.
X is at least 5 and y is at least 668.
x+y=5+668=673
2.6 Volleyball team games, only one game for every two teams. Now it is known that the scores of each team are different (there is no draw in volleyball match, the team gets 1 point, and the team loses 0 point), with Team A ranking third and Team B ranking fourth. I want to ask: Who won the match between Team A and Team B? And explain why.
Six volleyball teams played, and every two teams just played one game, which means they played 15 games, so it was always * * *
Yes 15 points
It is known that the scores of each team are different, so the scores are: 0, 1, 2, 3, 4, 5.
Moreover, the front ones lost to the back ones (according to the above scores).
We know that A is 3 points and B is 2 points.
win
3. There are two △ABC and △A'B'C' painted yellow and blue respectively, where ∠ c = ∠ c' = 90, and the two triangles are not similar. Question: Can you separate these two triangles with a straight line, so that △ABC can be divided into two yellow triangles and △A'B'C? If yes, please design a subdivision scheme, if not, please explain the reasons.
The x power of 4.25 is equal to 2000, and the y power of 80 is equal to 2000. Try to prove that 1/X+ 1/Y= 1.
The x square of 25 is equal to 2000, 25 *80=2000, that is, Q 80 consists of several 25s, plus the above 25, that is, X=80/25+ 1= 105/25. Similarly, Y = 25/80+65438+. 1/X=25/ 105， 1/Y=80/ 105， 1/X+ 1/Y = 25/ 105+80/ 105 = 105/ 105 = 1
5. Let x and y satisfy x+3y+ (absolute value sign) →@3x-y@= 19, 2x+y=6, then x=? y=？
If 3x-y is less than 0, for 4y-2x= 19 and 2x+y=6, X=0.5 Y=5.
The other situation is not true.
6. Given that the equation x 2-6x+q = 0 can be formulated as (x-p) 2 = 7, then x 2-6x+q = 2 can be formulated as follows.
A.(x-p)^2=5·x-p)^2=9
C.(x-p+2)^2=9 D.(x-p+2)^2=5
X 2-6x+q = 0 and (x-p) 2 = 7 are a formula, and the comparison coefficient is expanded.
p==3，q==2