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Chapter Overview
Learning Goals
Learning Goals
Maths
Types of numbers
Number calculations
Fractions, decimals and percentages
Algebraic manipulation
Formulae and equations
Straight line graphs
Other graphs
Ratio
Proportion
Rates of change
Shapes
Properties of shapes
Lines and angles
Drawing shapes
Trigonometry
Probability
Maths
Summary
Triangles can be classified as right-angled, equilateral, isosceles or scalene, depending on their properties. All interior angles in a triangle add up to 180°. A regular polygon is a polygon with equal sides and equal interior angles.
Triangle | properties | Diagram |
Equilateral |
| |
Isosceles |
| |
Scalene |
| |
Right-angled |
| ![]() |
A regular polygon is a polygon with equal sides and equal interior angles.
Regular polygon | Interior angles | Number of sides | Diagram |
Equilateral triangle | 60° | 3 | |
Square | 90° | 4 | |
Pentagon | 108° | 5 | |
Hexagon | 120° | 6 | |
Heptagon | 128.6° | 7 | |
Octagon | 135° | 8 |
Can you identify the type of triangle based on its properties described below?
First, it can help to sketch the triangle.
Based on these properties, the shape is a right-angled isosceles triangle.
Is a shape with eight equal sides and eight equal interior angles a regular polygon?
Yes, as all shapes with equal sides and equal interior angles are regular polygons.
This shape is an octagon.
Triangles can be classified as right-angled, equilateral, isosceles or scalene, depending on their properties. All interior angles in a triangle add up to 180°. A regular polygon is a polygon with equal sides and equal interior angles.
Triangle | properties | Diagram |
Equilateral |
| |
Isosceles |
| |
Scalene |
| |
Right-angled |
| ![]() |
A regular polygon is a polygon with equal sides and equal interior angles.
Regular polygon | Interior angles | Number of sides | Diagram |
Equilateral triangle | 60° | 3 | |
Square | 90° | 4 | |
Pentagon | 108° | 5 | |
Hexagon | 120° | 6 | |
Heptagon | 128.6° | 7 | |
Octagon | 135° | 8 |
Can you identify the type of triangle based on its properties described below?
First, it can help to sketch the triangle.
Based on these properties, the shape is a right-angled isosceles triangle.
Is a shape with eight equal sides and eight equal interior angles a regular polygon?
Yes, as all shapes with equal sides and equal interior angles are regular polygons.
This shape is an octagon.
FAQs
Question: What shape has three equal sides and three equal interior angles, and what kind of polygon is it?
Answer: A shape with three equal sides and three equal interior angles is an equilateral triangle, which is a regular polygon.
Question: What are the four types of triangle?
Answer: The four types of triangle are right-angled, equilateral, isosceles and scalene.
Question: What is a regular polygon?
Answer: A regular polygon is a polygon with equal sides and equal interior angles.
Theory
Exercises
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