The 5 Angle Rules

All you need for almost any angle problem

11

22

33

44??

?

??

11

22

33

Parallel lines

44

• 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, s

o

all angles 60o

55

The 5 Angle Rules

All you need for almost any angle problem

11

22

33

44

?

?

?

??

Total angles in 3 triangles = 3 x 180 = 540o

What is the smallest number of triangles you can split this shape up into?

So total angles in a pentagon = 540o

4 triangles = 4 x 180 = 720o

Hexagon = 6 sides

5 triangles = 5 x 180 = 900o

Heptagon = 7 sides

10 triangles = 10 x 180 = 1800o

Dodecagon = 12 sides