1. All you need for almost any angle problem
The 5 Angle Rules
All you need for almost any angle problem ? 3 1 ? ? 2 ? 4 ?

2. 1 2 3

3. Parallel lines 4

4. 5 Any Triangle All angles add up to 180o Special triangles:
Isosceles Triangle:
2 equal angles
Equilateral Triangle:
3 equal angles (all 60o)
Only need 1 angle to find all the rest
All angles equal, so all angles 60o

5. All you need for almost any angle problem
The 5 Angle Rules
All you need for almost any angle problem 3 ? 1 ? ? 2 4 ? ?

6. What is the smallest number of triangles you can split this shape up into?
Total angles in 3 triangles = 3 x 180 = 540o
So total angles in a pentagon = 540o

7. Hexagon = 6 sides
4 triangles = 4 x 180 = 720o

8. Heptagon = 7 sides
5 triangles = 5 x 180 = 900o

9. Dodecagon = 12 sides
10 triangles = 10 x 180 = 1800o