There are three types of angles: right angles which measure 90 degrees, obtuse angles which measure more than 90 degrees, and acute angles which measure less than 90 degrees. There are also three types of triangles classified by their sides: equilateral triangles have three equal sides and three equal 60 degree angles, isosceles triangles have two equal sides and two equal angles, and scalene triangles have no equal sides and no equal angles.

1. ANGLE
Types of angles

2. Types of angles:
1. RIGHT-ANGLED
2. OBTUSE
3. ACUTE

4. One right angle 90º
90º
RIGHT-ANGLE

6. One obtuse angle: >90º
>90º
OBTUSE TRIANGLE

8. acute angle: <90º
<90º
ACUTE ANGLE

9. TRIANGLE
Types of triangles

10. According to the sides:
1. EQUILATERAL
2. ISOSCELES
3. SCALENE

11. According to the sides:

12. According to the sides: EQUILATERAL
3 equal sides

13. According to the sides: EQUILATERAL
3 equal sides
3 equal angles
60º 60º
60º

14. According to the sides:

15. According to the sides: ISOSCELES
2 equal sides

16. According to the sides: ISOSCELES
2 equal sides
2 equal angles

17. According to the sides:

18. According to the sides: SCALENE
no equal sides

19. According to the sides: SCALENE
no equal sides
no equal angles