First, multiple-choice questions:
1, the following reasoning is correct ()
A, ∫≈ 1 and ∠2, ∠2 and ∠3, ∴1and ∠3.
B, ∫≈ 1 and ∠2 are antipodal angles, ∠2=∠3, ∴∠ 1 and ∠3 are antipodal angles.
C, ∫∠ 1 and ∠2 are complementary, ∠2 and ∠3 are complementary, ∴∠ 1=∠3.
d、∵a⊥b,a⊥c,∴b⊥c
2. Schools, factories and TV towers are represented by points A, B and C respectively. The factory is 30 northwest of the school and the TV tower is 55 southeast of the school, so ∠BAC in this picture is equal to ().
a、85b、 175 C、 145D、 155
3. As shown below, there are four conclusions: ① If ∠ 1=∠2, then AB//CD; ② If ∠ 1=∠2, then AD//BC;
③ If ∠3=∠4，AB//CD； ④ If ∠3=∠4, AD//BC, in which the correct one is ().
A, ① and ②b, ③ and ④c, ① and ④d, ② and ③.
4. As shown in the figure below, AB ⊥ ef, CD ⊥ ef, AF//BG and BG are equally divided into ∠ABE, so there are () angles in the figure equal to ∠ 1.
a、 1 B、2C、3D、4
5. As shown in the figure, when straight line C intersects with straight lines A and B, a/b, the following conclusions are obtained: ①∠ 1=∠2, ②∠ 1=∠3, ③∠3=∠2.
A, B, 65438+ C, 2D, 3
6, as shown in the figure, in the following conditions, can determine the AB//CE is ().
A、B=∠ACE B、A=∠ECD C、B=∠ACB D、A=∠ACE
Question 3, Figure 4, Figure 5, Figure 6
Second, fill in the blanks:
7, a 0.5cm long hair with a magnifying glass to observe its length is 5cm, then an angle observed under the magnifying glass 15 should be _ _ _ _.
8. As shown on the right, AB and CD intersect at point O, and OB bisects ∠DOE.
If ∠ doe = 60, ∠ AOC = _ _ _ _
9. If the complementary angle of an angle is 3 times larger than that of this angle 18, then the degree of this angle is _ _ _ _ _.
10, as shown in the right figure, AB//EF//CD, ∠A=72, ∠D= 18,
The positional relationship between AE and DE is _ _ _ _ _
1 1, two complementary angles are equal, and their complementary angles are _ _ _
12, if a⊥b, b//c, then a _ _ _ c.
13, as shown in the figure, is a part of the trapezoidal upper bottom, and it has been measured that ∠A = 120∠D = 100.
Then the degrees of the other two angles of the trapezoid are _ _ _ _ _.
Three: Answer the question:
14, a classmate is playing bumper cars in the playground and starts to drive east. On the way, he turned 50 turns to the right and then drove on. After walking for a while, he turned 50 turns to the left.
(1) Is the direction of bumper cars the same as before? What is your basis?
(2) If the angle of the bumper car turning left for the second time is 40 or 70, is the car driving in the same direction as before? What is your basis?
(3) From the above situation, do you know what conditions are met and the driving direction of the car is the same as before?
15, (senior high school entrance examination) as shown in the figure, AB//CD,EG⊥AB, the vertical foot is g, if ∠ 1=50, find the degree of ∠ e.
16, as shown in figure AB//CD. What is the relationship between ∠A, ∠C and ∠E? Please explain the reason.
17 as shown in the figure, given any point m on the edge of ∠AOB and OA, find a straight line parallel to OB at the point m (you need to draw with a ruler).
Chapter II Answers to Test Questions
First, multiple-choice questions:
1、C2、D3、D4、D5、D6、D
Second, fill in the blanks:
7, 158, 309, 36 10, mutually perpendicular 1 1, 135 12,
13, 60 and 80
Third, answer questions:
Two straight lines with the same angle as 14 and (1) are parallel.
(2) Different, the same angle is not equal.
(3) When the first turn and the second turn have the same degree, the driving direction is the same.
15,∠E = 40
16,∠C =∠A+E
17, sketch