Derive and use the sum of angles in a triangle and use it to deduce the angle sum in any polygon, and to derive properties of regular polygons
| 1. | Triangle Tangle - Determine the size of an angle in a triangle given an algebraic expression for the relationship between the 3 angles | |
| 2. | Tri-Trip - angle sum of a triangle | |
| 3. | Tri-trip Terry - angle sum of a triangle | |
| 4. | Top Of The Tower Triangle - calculate size of angles in isosceles triangle, angle sum of a triangle | |
| 5. | Ancient Angles - calculate size of base angles in isosceles triangle, angle sum of a triangle | |
| 6. | Angling With Ants - calculate angle size, angle sum of a triangle | |
| 7. | ABCs 1 - triangle geometry, equal angles opposite equal sides | |
| 8. | Tricky Triangles 4 - calculate reflex angle of equilateral triangle | |
| 9. | Tricky Triangles 3 - calculate size of angles in isosceles triangle, angle sum of a triangle, reflex angles | |
| 10. | Tricky Triangles 2 - calculate size of angles in isosceles triangle, angle sum of a triangle | |
| 11. | Tricky Triangles 1 - calculate size of angles in isosceles triangle, angle sum of a triangle | |
| 12. | Shape Up! 10 - calculate angle size, supplementary angels, angle sum of a triangle | |
| 13. | Shape Up! 9 - angle sum of a triangle, exterior angles, revolution | |
| 14. | Phoebe's Triangle Theorems 1 - angle sum of a triangle | |
| 15. | Shape Up! 5 - calculate angle size, angle sum of a triangle | |
| 16. | Shape Up! 4 - calculate size of angles in isosceles triangle, angle sum of a triangle |