Page 97 - Knowledge Organiser Yr8 24-25

Knowledge Base: Mathematics TOPIC 16: Angle Reasoning Year 8 | Autumn Term 2
By the end of this topic you should be able to:
• Use angle facts
• Find angles in triangles
• Find angles in parallel lines
• Find angles in quadrilaterals
• Recognise properties of polygons
• Find interior and exterior angles in polygons
• Complete exam questions using angle reasoning
Angle
Perpendicular
Parallel
A measure of turn given in degrees
Lines which meet at right angles
Lines which are always the same difference apart
900 is a quarter turn or right angle
Horizontal and vertical lines are perpendicular
Railway tracks are parallel
Language
Meaning
Example
Alternate angles
When referring to parallel lines: ‘Z shaped’ pairs of angles
Alternate Corresponding
Corresponding angles
When referring to parallel lines: ‘F shaped’ pairs of angles
Polygon
A closed 2D shape
It is a regular polygon when all the sides and angles are equal
A triangle is a type of polygon
An equilateral triangle is a regular polygon
Interior angle
An angle inside a polygon
Interior Exterior
Exterior angle
The angle made between the side of a polygon and its extension
Congruent
Two shapes are congruent if they are exactly the same shape and size
These triangles are all congruent
Important things to remember:
“Give reasons” means use you must explain WHY something is true, not just write out the calculation that you did
Worked examples
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