In this lesson you will learn what the angles in a triangle add up too and how to calculate missing angles in a triangle. Rob starts this lesson by showing you a very cool exercise that proves how many degrees there are in a triangle. You can also do this yourself at home.

The questions covered in this lesson are i) find angle $x$, give a reason for your answer

ii) find angle $x$, give a reason for your answer

Naming angles

Proving angles on a straight line add to 180

Angles on a straight line

Angles on a straight line - Common Mistake

Angles on a straight line - Exam style question

Proving the angles around a point add up to 360

Angles around a point

Angles around a point - Exam style question

Finding angles in quadrilaterals

Introduction to Isosceles triangles & finding the base angles

Finding angles in Isosceles triangles

Finding angles in Isosceles triangles - Exam style question

Introduction to Equilateral triangles

The 4 types of Triangles

Vertically opposite angles

Vertically opposite angles exam question

3 letter angle notation

Area

Compound Areas

Surface Area

Volume

Circles

Circle Geometry (Higher Only)

Angles

Angles on Parallel Lines

Measuring Angles

Polygons

Properties of Shapes

Midpoints of Lines

3D Coordinates (Higher Only)

Converting Units of Length, Area and Volume

Similar Triangles and Similar Shapes (Higher Only)

Loci and Constructions

Bounds (Higher Only)

Converting Metric Units

Converting Imperial Units

Pythagoras Theorem

Right-angled Trigonometry

Non-right Angled Trigonometry (Higher Only)

3D Pythagoras (Higher Only)

3D Right-angled Trigonometry (Higher Only)

Bearings

Density

Congruence

Translations

Reflection

Rotation

Enlargements

Describing Single Transformations

Vectors