**This is the students’ version of the page. Log in above for the teachers’ version.**

Prerequisites

- G3a – Angles at a point, angles at a point on a straight line, vertically opposite angles
- G3b – Alternate and corresponding angles on parallel lines
- Knowledge of the definition of “regular” is also assumed

# Part 1 – The sum of angles in a triangle

Teacher resources for Part 1

**Teachers**: log in to access the following:

- Slides in PPTX (with click-to-reveal answers)
- Slides in PDF (one slide per page, suitable for importing into IWB software)

- Worksheet (with space for student work)
- Handout (slides with exercises only; 4 per page for reduced printing)

- Skills drill worksheet – Isosceles triangles and angles (15 questions on one side of A4; answers included – requires knowledge of G4a)

- Random Question Generator: Isosceles triangles and angles (requires knowledge of G4a)

Links to past exam questions

**Teachers**: log in to access these.

# Part 2 – Angle properties of polygons

Teacher resources for Part 2

Links to past exam and UKMT questions

**Teachers**: log in to access these.

In the real world

**Teachers**: log in to view this content.

Check out this article on geodesic domes from the Buckminster Fuller Institute for more – and note the equilateral triangles making up the dome in the article’s main image.