Teach Genie
Teach it back in your own words, spot gaps, and remember it better.
Parallel lines stay the same distance apart and never meet. We write AB∥CDAB \parallel CDAB∥CD when two lines are parallel.
A transversal is a line that cuts across two or more lines. Before using parallel-line rules, keep basic facts ready: angles on a straight line add to 180∘180^\circ180∘, vertically opposite angles are equal, and angles in a triangle add to 180∘180^\circ180∘.
In a written solution, each new angle needs a reason. Common reasons include angles on a straight line, vertically opposite, corresponding, alternate, co-interior, and angles in a triangle.
Question 1
4 marksAB AB\,AB and CD CD\,CD are parallel lines.
What is the angle sum on a straight line?
Revision notes for Edexcel GCSE Maths Angles in Parallel Lines. Open the guide for explanations and worked examples. Written against the Edexcel GCSE Maths (1MA1) specification, so the content matches what's examinable rather than general Maths background.
1 of 4
Two parallel lines are cut by a transversal. The top-right angle at the upper intersection is 72∘72^\circ72∘, and xxx is the top-right angle at the lower intersection. What is xxx?
