1. Heron’s formula

3. Introduction to heron’s formula

4. Introduction of another formula for area of a triangle
Most of us are aware with :
Area of a triangle =
Where b = base and h = corresponding height of the triangle

5. Examples : 1) Find the area of a triangle having sides : AB = 4 cm
BC = 3 cm
CD = 5 cm

6. Solution of Example 1)

7. Continue…

8. Example 2:
2) Rahul has a garden, which is triangular in shape. The sides of the garden are 13 m, 14 m, and 15 m respectively. He wants to spread fertilizer in the garden and the total cost required for doing it is Rs 10 per m2. He is wondering how much money will be required to spread the fertilizer in the garden

9. Solution of Example 2) Given a = 13 m , b = 14 m and c = 15 m
So , we will find
the area of the
triangle by
using Heron’s
formula.

10. Continue..

11. Continue … Given the rate = Rs 10 per m^2 Now :
Total cost = Rs. 10 * 84 = Rs 840/-

12. Area of a quadrilateral
Suppose there is a quadrilateral
having sides : a , b , c and d and
diagonal r.
The diagonal d divides the quadrilateral into 2 triangles.
So : Ar(ABCD)= Ar(ABD) + Ar(BCD)

13. Continued Area of triangle : ABD Heron’s formula:
Putting the values we get :

14. Continued..

16. Solution of example
As we have the formula written below for the area of a quadrilateral
Where :
a = 4cm
b = 3 cm
c = 5 cm
d = 6 cm
And r (diagonal ) = 7 cm

17. cm2
Click on this arrow to continue

18. How to find the area of an equilateral triangle

19. Concept based question
What equilateral triangle would have the same area as a triangle with sides 6, 8 and 10?

20. Solution
First of all we will find the area of the triangle having sides : a = 6 units , b = 8 units and c = 10 units

21. THE END…