### Category: Compass & Straight Edge

## 5. The Centre of a Triangle

Using a compass and straight edge, we find the four traditional centres of a triangle : i.e. the incentre, the circumcentre, the orthocentre and the centroid. We also look at the Medial Triangle, and the Euler Line. The Centre of a Triangle (Compass and Straight Edge) PowerPoint Lesson: Compass and Straight Edge – The […]

## 1. Angles-Introductory Terms

In this video, Teacher Jon introduces the basic terms students need for the study of Angles. Video Lesson: Download Worksheet (PDF): ANGLES-Introductory Terms

## 2. Easy Angle Problems

In this lesson, Teacher Jon provides some easy angle problems, for Lower Secondary Maths students, but a basic knowledge of the terms and symbols used in Angles is still required– (for instance, see my video on Angles – Introductory Terms) . Video Lesson: Download Worksheet (PDF): ANGLES – Easy Angles Problems

## 3. The World’s Two Hardest Easy Geometry Problems

In this video, Teacher Jon sets out how to solve these two well known geometry problems using only isosceles, equilateral and congruent triangles. Video Lesson: Download Worksheet (PDF): World’s Two Hardest Easy Geometry Problems(Geometry-Angles)