3.Valid,Parallel lines are coplanar (they lie in the same plane) and never intersect.
4.Valid,Linear pair of angles are formed when two lines intersect each other at a single point. The angles are said to be linear if they are adjacent to each other after the intersection of the two lines. The sum of angles of a linear pair is always equal to 180°.
Answers & Comments
1. Not Valid
2. Valid
3. Valid, Parallel lines are coplanar (they lie in the same plane) and never intersect.
4. Valid, Linear pair of angles are formed when two lines intersect each other at a single point. The angles are said to be linear if they are adjacent to each other after the intersection of the two lines. The sum of angles of a linear pair is always equal to 180°.
5. Not Valid
6. Not Valid