Answer:
180°
Explanation:
When any 2 lines make an angle of 180° , they are called as parallel lines . In this case both the lines never intersect each other.
When any 2 lines make an angle of 90° , they are called as perpendicular lines . Both the lines intersect each other.
( Usually most get confused in this question and do write 90° or 0° but 180° is the correct answer)