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This topic covers angle facts — angles on a line, around a point, in triangles and quadrilaterals, and in parallel lines — and finding missing angles with reasons. It's a core topic in GCSE and iGCSE Maths with Edexcel and the other major boards. This free interactive eClassroom course walks through each step with worked examples and instant-feedback questions, so you can practise until it's secure.
How you do it
Use the angle facts in order: angles on a straight line total 180, around a point 360, in a triangle 180 and in a quadrilateral 360. With parallel lines, look for the F, Z and C shapes giving corresponding, alternate and co-interior angles. Give a reason for every step.
Before you start
It assumes you can handle basic shape properties. Assessed at Foundation and Higher tier. The same ideas return in polygons, circle theorems and trigonometry. Filed under Geometry.
What you learn
A handful of key facts let you find missing angles on lines, around points, in triangles, and between parallel lines. When two straight lines cross, vertically opposite angles are equal. The course works through angles on a line and around a point, vertically opposite angles and triangles and angles in parallel lines. Every section has instant-feedback practice questions matched to Edexcel iGCSE 4MA1 and the other major GCSE boards, and the course finishes with full exam-style questions you mark yourself.
Related Topics
We teach Angles as one of the Geometry topics in our GCSE course library, at Foundation tier. The course is built from 3 concept sections, 2 worked examples and 3 check points before the exam-style set. Nearby topics in the same strand are Area & Perimeter, Circle Theorems, Circles, Loci & Construction and Pythagoras' Theorem. You can drill this strand further on the Geometry revision engine, with your accuracy saved to your skill tree.
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