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 5 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and 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
Practice questions for Angle Facts
An angle measures 135°. What type of angle is this?
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.
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°