### Interior angles in a triangle

In this lesson, we will learn about the interior angles in a triangle, and how to find unknown angles in various types of triangles.

Skip navigation# Unit Overview: Angles in polygons

## Lessons:

### Interior angles in a triangle

### Categorising and defining polygons

### Building shapes from triangles (Part 1)

### Building shapes from triangles (Part 2)

### Polygons and triangles

### Generalising angles in polygons (Part 1)

### Generalising angles in polygons (Part 2)

### Finding missing angles in polygons

### Exterior angles

### Regular interior and exterior angles (and mean of irregular)

### Generalising and comparing generalisations

### Angle notation and problem solving

12 lessons

In this lesson, we will learn about the interior angles in a triangle, and how to find unknown angles in various types of triangles.

In this lesson, we will learn about the key terminology involved in describing polygons, and begin to categorise polygons, based on certain properties.

In this lesson, we will learn how to arrange triangles to form polygons as part of an investigation into the internal angles of polygons. This represents part 1 of a two-part lesson.

In this lesson, we will learn how to arrange triangles to form polygons as part of an investigation into the internal angles of polygons. This represents part 2 of a two-part lesson.

In this lesson, we will learn that the sum of the interior angles of a polygon can be found using triangles.

In this lesson, we will learn how to generalise the sum of the interior angles in an n-sided polygon.

In this lesson, we will learn how to apply the generalisation of the total interior angles in an n-sided polygon.

In this lesson, we will learn how to find an unknown angle in a polygon.

In this lesson, we will learn about exterior angles, and how they sum to 360 degrees.

In this lesson, we will learn how to calculate the mean interior and exterior angles of n-sided polygons, and solve problems based on these formulae.

In this lesson, we will combine everything learnt so far about angles in polygons to compare how specific examples relate to generalised cases.

In this lesson, we will learn about how to problem solve with angles in polygons, along with learning notations for referring to angles.

Units in Maths

- Numbers and numerals
- Axioms and arrays
- Factors and multiples
- Order of operations
- Positive and negative numbers
- Expressions, equations and inequalities
- Angles
- Classifying 2-D shapes
- Constructing triangles and quadrilaterals
- Coordinates
- Area of 2-D shapes
- Transforming 2-D figures
- Prime factor decomposition
- Conceptualising and comparing fractions
- Manipulating and calculating with fractions
- Ratio
- Percentages
- Different number systems
- Sequences
- Forming and solving equations
- Forming and solving inequalities
- Linear graphs
- Accuracy and estimation
- Algebra and problem solving
- Ratio (8.6a)
- Ratio, real life graphs, and rates of change
- Direct and indirect proportion
- Univariate data
- Bivariate data
- Famous maths problems
- Angles and parallel lines
- Angles in polygons
- Bearings
- Volume and surface area of prisms
- Area review
- Circles
- FDP review (9.1a)
- Probability
- Sets and Venn Diagrams
- Solving linear simultaneous equations algebraically
- Solving linear simultaneous equations graphically
- Angle review (9.5a)
- Constructions, congruence, and loci
- Pythagoras's theorem
- Famous maths problems
- Ratio review (9.7a)
- Similarity and enlargement
- Surds and trigonometry
- Quadratic expressions (9.9)
- Quadratic equations (9.10)
- Indices and standard form
- Growth and decay
- Finance

- Ratio review (9.7a)
- Constructing triangles and quadrilaterals
- Angles
- Shape and patterns
- Angles and shape
- Constructions, congruence, and loci
- Faces, shapes and patterns; lines and turns
- 3D Shape
- Coordinates
- Angles
- Classifying 2-D shapes
- Shape and pattern
- Transformations
- Angles in polygons
- Circles
- Pythagoras's theorem
- 2-D Shape and Symmetry
- Transforming 2-D figures
- Bearings
- Area of 2-D shapes
- Missing angles and lengths
- Coordinates and shape
- Shape and sorting
- 2-D and 3-D shape
- Volume and surface area of prisms