Watch out
Writing an angle without a reason.
Scottish National 5 Mathematics
National 5 Maths Angle properties
Use at least two linked angle facts in polygons, triangles, quadrilaterals and circles.
Formula reference
Check the National 5 rules and formulae linked to this topic.
Which method?
Match exam clues to a suitable method.
Before you start
- Mark every angle fact you can justify.
- Be ready to work exactly without a calculator and show each mathematical step.
- Read the command word, record the units or requested form, and make the final answer match it.
Explanation
Angle properties is an assessed part of Scottish National 5 Mathematics in the geometry area. Use at least two linked angle facts in polygons, triangles, quadrilaterals and circles.
Mark every angle fact you can justify.
Work through one relationship at a time.
State the reason beside each calculation.
The interactive bank below mixes direct skills, reverse questions, interpretation and contextual reasoning rather than repeating one number pattern.
Key formulae and rules
- angles in a triangle total 180°
- interior angle sum of an n-gon = (n − 2) × 180°
Check
Add the completed angles using the relevant total to confirm that no angle fact has been counted twice.
Exam tip
Mark the diagram with the values you use, show the formula and finish with the correct length, area or volume units.
Worked examples
Worked example 1
Angle properties worked example
An isosceles triangle has vertex angle 38°. Find each base angle.
- The base angles are equal.
- Each is
Answer: 71°
Watch out
- Writing an angle without a reason.
- Using a diagram's appearance instead of stated properties.