Summary

1. If a stands on a line, then the sum of the two adjacent angles so formed is 180°.

2. If the sum of two adjacent angles is 180°, then the non-common arms of the angles form a .

3. Both these together are called as the Linear pair axiom.

4. Two lines are intersecting when they share a common pointhave the same line equation.

5. If two lines intersect each other, then the vertically opposite adjacent alternately opposite angles are equal.

6. Lines which are parallel to a given line are to each other.