1. Triangles

2. Equilateral Triangle:
Types of Triangles
Equilateral Triangle:
All sides and all angles are equal.
Isosceles Triangle:
Two sides and two angles are equal.

3. Right-Angled Triangle:
Types of Triangles
Right-Angled Triangle:
One angle is a right angle (900).
The side opposite the right angle is called the Hypotenuse
Scalene Triangle:
No equal sides and no equal angles.

4. Calculating Missing Angles
Example 1 - Calculate the value of a:

5. Calculating Missing Angles
Example 2 - Calculate the value of H:

6. Calculating Missing Angles
Example 3 - Calculate the value of I:

7. Calculating Missing Angles
Example 4 - Calculate the value of x:

8. Calculating Missing Angles
Example 5 - Calculate the value of x: