If ∠ BOC = 120, ∠ A = _ _ _ _ _
2. calculation; a3m-2÷a2m+ 1 =；
3. In Rt△ABC, ∠ C = 90, ∠A is twice as much as ∠B, then ∠ A = _ _ _ _ _ _
Xiao Ming has two sticks of 4cm and 8cm. He wants to make an isosceles triangle with these two sticks, and he needs another stick _ _ _ _ _ cm long.
5. Throw a dice casually, and the probability of throwing an odd number is _ _ _ _ _ _ _ _; Flip a coin twice and the probability that both tails are up is _ _ _ _ _ _ _ _.
6. There is an atom with a diameter of about 0.00000053 meters, which can be expressed as _ _ _ _ _ _ by scientific counting.
7, axisymmetric graphics have _ _ _ _ axis of symmetry.
8. As shown in the figure ∠ 1+∠ 2 = 284, b∨c,
Then ∠3=, ∠4=.
9. The divisor of1.96 is accurate to _ _ _ _ _ _ _ _; The approximate value of 3698000 (with 3 significant figures) is
10, there are 26 capital letters in the mirror, including _ _ _ _ _ _ _ _ _ _ _ (no less than 4 letters).
Second, the choice (3 points for each small question, *** 15 points)
1, the following operation is correct ().
A.； b； c； d .
2. The candle is 20cm long and burns 5cm every hour after lighting. The relationship between the remaining height h (cm) and the time t (h) is ().
hahaha
3. If one angle of an isosceles triangle is 40, its base angle is ().
A, 100 b, 40 c, 70 d, 70 or 40.
4. The following graphics, axisymmetric graphics have ().
① Angle; ② line segment; ③ isosceles triangle; ④ equilateral triangle; ⑤ Triangle.
a . 1； B.2c . 3； D. four.
5. There are () correct figures in the following questions.
(1), two angles and the opposite side of an angle correspond to the congruence of two triangles ();
(2) The diagonal of two sides and one of them corresponds to the congruence of two triangles ();
(3) Three angles correspond to congruence of two equal triangles ();
(4), two symmetrical figures are congruent ();
(5) The maximum angle of a triangle is not less than 60 degrees ().
a、 1 B、2 C、3 D、4
Iii. Answer: (5 points for each small question, ***40 points)
1 、(—2003)0 ×2÷ +(— )— 2 ÷2— 3 2 、( 2x + a)2 —(2x—a)2
3. Draw the other half of the graph with the straight line L as the symmetry axis. 4 、( 9x 3y 2—6x 2y+3xy 2)÷(—3xy)；
5. Given that a+= 3, find the value of a2+. 6 、( x+y+z)(x-y-z)
7. Simplify the assessment:
, in which
8. It is known that ∠ α, ∠β, line segment A, and find △ABC, so that ∠B=∠α, ∠C=∠β, BC = A.
(Keep drawing traces, don't write)
Fill in the blanks on the horizontal line in the following procedure, and indicate the reasons in brackets. (5 points, 0.5 points will be deducted for each mistake, until the deduction is finished! )
Known: as shown in figure BC∨EF, BC=EF, AB = DE.
Explain that AC equals EF.
Solution: ∫BC∨EF (known)
∴∠ABC=∠__________()
In △ABC and △DEF,
______=_______
∵ _______=________
______=________
∴△ABC≌___________()
∴ _______=__________ ( )
Verb (abbreviation of verb) (6 points)
This painting shows a traveler leaving the city for the suburbs at 8 am.
A diagram of the change of distance and time. Answer the questions according to the pictures.
How far did (1) travel at 9: 00, 10: 30 and 12: 00 respectively?
A:
(2) How long did he rest?
A:
(3) The time it took him to get to his destination from rest.
What is the average speed?
Six, exploration (7 points)
1, as shown in figure, DE⊥AB, DF⊥AC,AE=AF, find a pair of congruent triangles and explain the reasons.
Seven. (7 points) As shown in the figure, it is known that AB =DE, BE = CF. What conditions should be attached to make △ ABC △ def? And explain why.