### Interior angles in a triangle

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

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

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

In this lesson, you will learn how to arrange triangles to form polygons (part I).

In this lesson, you will learn how to arrange triangles to form polygons (part II).

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

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

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

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

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

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

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

Units in Maths

Units in Geometry

- 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 (8.7a)
- Ratio, real life graphs, and rates of change
- Direct and indirect proportion
- Univariate data
- Bivariate data
- Famous maths problems
- Angles and parallel lines review
- Angles in polygons
- Bearings
- Volume and surface area of prisms
- Area review
- Circles
- FDP review (9.1a)
- Probability
- Sets, Venn and sample space 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)
- Angles
- Constructing triangles and quadrilaterals
- Constructions, congruence, and loci
- Shape and patterns
- Angles and shape
- Faces, shapes and patterns: lines and turns
- Coordinates
- 3D Shape
- Angles
- Classifying 2-D shapes
- Transformations
- Shape and pattern
- Circles
- Angles in polygons
- Pythagoras’s theorem
- Bearings
- Transforming 2-D figures
- 2-D Shape and Symmetry
- 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