1. Triangles

2. identifying triangles 1
more than 3 sides  not a triangle
3 sides  triangle
less than 3 sides  not a triangle
3 sides, but some curved  not a triangle

3. identifying triangles 2no
yes

4. parts of a triangle A B C vertex angle A side AB side AC angle B
side BC
angle C C
vertex

5. types of triangles 1 all sides are equal
so they are equilateral triangles

6. types of triangles 2 Which side is different? Are all sides equal?
Which side is not?
In this one?
Are all sides equal for this one?
Which side is not equal to the other sides?
2 sides are equal in each
so they are isosceles triangles

7. types of triangles 2 X Y Z A B C D M S P Q R Which 2 sides are equal?
How are these angles?
Which side is the largest?

8. types of triangles 3 Which sides? Are any pair of sides equal?
No pair of sides is equal
so they are scalene triangles

9. types of triangles 4 all angles are acute
so they are acute angled or acute triangles

10. types of triangles 5 1 angle is right
so they are right angled or right triangles

11. types of triangles 6 1 angle is obtuse
so they are obtuse angled or obtuse triangles