4.2.1
Polygons
Regular Polygons
Regular Polygons
A regular polygon is a many sided shape where all the sides are the same length and all the angles are the same size. The order of rotation and the number of lines of symmetry of a regular polygon are the same as the number of sides.
Angles in a Polygon
Angles in a Polygon
The interior (inside) angles of a polygon (a shape made of straight lines) are the angles inside the shape.


Interior (inside) angles
Interior (inside) angles
- The sum of the interior angles is (n - 2) × 180° where n is the number of sides the polygon has.


Exterior angles
Exterior angles
- If you extend the side of a polygon outside the shape then the exterior angle is the angle between the extended line and the adjacent edge.
- The exterior angles add up to 360°.
- In a regular polygon the exterior angle + interior angle = 180°.
1Numbers
1.1Integers
1.3Decimals
1.4Powers & Roots
1.5Set Language & Notation
1.6Percentages
1.7Ratio & Proportion
2Equations, Formulae & Identities
2.1Algebraic Manipulation
2.2Expressions & Formulae
2.3Linear Equations
2.4Quadratic Equations
2.5Proportion
3Sequences, Functions & Graphs
3.1Sequences
3.3Graphs
3.4Common Graphs
4Geometry
4.1Angles, Lines & Triangles
4.2Polygons
4.5Circle Properties
4.6Trigonometry & Pythagoras’ theorem
4.7Mensuration of 2D Shapes
4.83D Shapes & Volume
5Vectors & Transformation Geometry
6Statistics & Probability
6.1Statistical Measures
6.2Graphical Representation of Data
Jump to other topics
1Numbers
1.1Integers
1.3Decimals
1.4Powers & Roots
1.5Set Language & Notation
1.6Percentages
1.7Ratio & Proportion
2Equations, Formulae & Identities
2.1Algebraic Manipulation
2.2Expressions & Formulae
2.3Linear Equations
2.4Quadratic Equations
2.5Proportion
3Sequences, Functions & Graphs
3.1Sequences
3.3Graphs
3.4Common Graphs
4Geometry
4.1Angles, Lines & Triangles
4.2Polygons
4.5Circle Properties
4.6Trigonometry & Pythagoras’ theorem
4.7Mensuration of 2D Shapes
4.83D Shapes & Volume
5Vectors & Transformation Geometry
6Statistics & Probability
6.1Statistical Measures
6.2Graphical Representation of Data
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