What a broken teacher of ours! We talked, the teacher got angry, let us write I am still us , thank

Your teacher is wrong. Straight lines perpendicular to each other can be spatial straight lines, perpendicular but not intersecting! You chose D, your teacher must have done it from the perspective of plane geometry, I don't know what the background of your question is, if it is plane geometry, then your teacher is right, if not, then congratulations, the teacher is wrong.

Choosing C is correct, but (4) is true. The other three propositions: (3) speak of straight lines, but do not say parallel lines. (1) Line segments perpendicular to each other may or may not intersect. (2) There can be many straight lines perpendicular to known straight lines.

It is right to choose C, (1) two straight lines perpendicular to each other do not intersect in some figures;

2) there are an infinite number of straight lines perpendicular to the known straight lines;

3) Since the two straight lines are parallel and the isotopic angles are equal, the question says that they are two straight lines;

4) This is the distance from a point to a straight line definition;

Therefore, only C is right, and only option 4 is right.

d, the title didn't say that it was on the same paper, so it was wrong.

Trust me, that's right! That's what our math teacher said! ）

To prove vertical, the provenance 90. That is to say, there must be angles in the vertical, and if there are corners, there must be intersections. Of course, the perpendicular segments intersect. You're wrong!

C should be chosen, but the fourth proposition is correct, your teacher is wrong.

Perpendicular to each other is intersecting. In a planar figure, there are two cases of lines, one intersects and the other is parallel, and perpendicular is one that intersects.

The landlord, the teacher is right, indeed, the intersection of two line segments perpendicular to each other must be a true proposition, hope!!

There's nothing wrong with that, perpendicular is intersecting, not parallel.

Brat! You know? Choose C! Buckle the word! Nima!

Perpendicular to each other intersects, perpendicular to intersection.

At least 2, 4 to c.

Tell you that the teacher doesn't know that the opposite side is vertical.

What the? What do you mean? Let's be clear!