Parallel lines are lines that never cross each other - they keep the same distance apart from each other. When two lines intersect, the opposite (X) angles are equal. On parallel lines, alternate ...

Learn about complementary, supplementary, corresponding, alternate and vertically opposite angles with BBC BItesize Scotland maths for Third Level CfE.

And thanks to geometry, we have a handy-dandy theorem for determining angles when two parallel lines are transected by a third line: alternate interior angles are congruent (or equal).

CBSE Class 9 Maths Chapter 6 Lines and Angles Extra Questions for 2020-21. Practice with these important questions to perform well in your Maths exam.