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Geometry & MeasuresDeep Dive

Method: Finding Missing Angles

Part of Angle Facts — GCSE Mathematics

This deep dive covers Method: Finding Missing Angles within Angle Facts for GCSE Mathematics. Revise Angle Facts in Geometry & Measures for GCSE Mathematics with 14 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 3 of 4 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 3 of 4

Practice

14 questions

Recall

12 flashcards

Method: Finding Missing Angles

1 Identify which angle fact applies (straight line, point, or vertically opposite)
2 Write an equation using the angle fact
3 Solve to find the missing angle
4 ALWAYS give a reason in your answer

Keep building this topic

Read this section alongside the surrounding pages in Angle Facts. That gives you the full topic sequence instead of a single isolated revision point.

The Essential Angle FactsWorked ExampleWhy Angle Facts Matter

Practice Questions for Angle Facts

An angle measures 135°. What type of angle is this?

  • A. Acute
  • B. Obtuse
  • C. Right angle
  • D. Reflex
1 markfoundation

Two angles on a straight line are 73° and 107°. A student says: 'These two angles must be equal because they are on a straight line.' Is the student correct? Give a reason for your answer.

2 markshigher

Quick Recall Flashcards

What is an acute angle?
An angle that is greater than 0° and less than 90°. Examples: 30°, 45°, 89°
What is a reflex angle?
An angle that is greater than 180° and less than 360°. Examples: 200°, 270°, 359°

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