(1) A straight line has only one vertical line.

⑵ There is only one straight line parallel to the known straight line.

(3) When two straight lines intersect, the four angles are equal and the two straight lines are perpendicular to each other.

(4) The distance from a point to a straight line is the vertical section of the point to a straight line.

The correct number is (b)

1。

The positional relationship between two straight lines in the same plane is (C)

A. Cross and vertical B. Parallel and vertical C. Cross or parallel D. Uncertainty

3 On the same plane, if two straight lines intersect with a third straight line, then these two straight lines (C)

A. Parallel B. Intersecting C. Parallel or intersecting D. Vertical

The number of straight lines that can be drawn through two of any three points is (A)

A. one or three B. three C. two D. i.

5 The parallel motion in the figure, referred to as translation, is determined by the motion (c).

A. direction B. distance C. direction and distance D. are all wrong

6 The following statement is incorrect (a)

A known straight line has countless parallel lines.

One and only one straight line is parallel to the known straight line.

One and only one straight line is perpendicular to the known straight line.

D if L 1 is parallel to L2 and L2 is parallel to L3, then L 1 is parallel to L3.

7 An angle is greater than its complementary angle, then this angle is (C).

A. acute angle B. right angle C. obtuse angle D. uncertainty

As we all know, straight lines AB and CD intersect at points O and O, and OA bisect each other.

After 20 years, 40 years, 50 years and 80 years.

9 In the following conditions, the positional relationship is perpendicular to each other (C)

A. the bisector of two opposite angles.

B. bisector of two complementary angles

The bisector of two adjacent corners in the four corners formed by the intersection of two straight lines.

D. bisector of two adjacent corners

10 When the main worker sets up the wires, in order to check whether the three wires are parallel, the main worker only checks whether two of them are parallel to the third wire. The reason is (d).

A. two points determine a straight line

B. between two points, the line segment is the shortest.

C crosses a point outside the straight line, and one and only one straight line is parallel to the known straight line.

D. If two straight lines are parallel to the third straight line, then the two straight lines are also parallel.