The document discusses how to calculate the area of a triangle by relating it to the area of a rectangle. The area of a triangle is equal to one-half the area of its related rectangle, which is formed by extending one of the triangle's sides to form the rectangle's base and using the triangle's height as the rectangle's height. This method can be applied to any triangle by identifying its base, height, and the corresponding related rectangle.

1. Area of Triangles What is the area of a triangle?

2. Triangle 1 Area of triangle ABC = ½ x area of related rectangle ABCD A B D C

3. Look at the height AB and base BC of triangle ABC. How are they related to the rectangle ABCD? A B D C Area of triangle ABC = ½ x area of related rectangle ABCD Triangle 2 They are the length and breadth of the rectangle!

4. A B D C E Area of triangle EBC = ½ x area of related rectangle ABCD Triangle 3

5. A B D C Area of triangle EBC = ½ x area of related rectangle ABCD E This is the figure you did just now. Did you manage to form it into a relate rectangle? Triangle 4

6. A B D C E F Area of triangle BED = ½ x area of related rectangle ABEF Triangle 5 This is the figure you did just now. Did you manage to form it into a relate rectangle?

7. What we have learnt… Area of triangle = ½ x area of related rectangle Area of triangle = ½ x Length x Breadth Area of triangle = ½ x Base x Height