To apply any formula to ** calculate area of a triangle**, one must know the value of at least one angle of the triangle. However, there is one formula for calculating the area of a triangle without measuring any of its angles.

In this article, we will use Heronâ€™s formula, named after the Hero of Alexandria, a Greek mathematician. It takes three lengths **(a,b, c)** of a triangle and semi-perimeter **s**. In order to apply this formula, it is mandatory to know the lengths of all three sides of the triangle.

## Formula

`A = âˆš`

*s* (*s* - *a*) (*s* - *b*) (*s* - *c*)

where, **a**, **b** and **c** are the lengths of sides of the triangle where s is half of the perimeter given by `s=(a+b+c)/2`

.

## Mathematical illustration

## Explanation

While coding, using Heron’s formula is not going to be a challenging task for you if you can compute the square root using a custom or built-in function. Now, let’s have a python program to evaluate the area of a triangle by using the length of the sides.

```
def calculateArea(a, b, c):
s= (a+b+c)/2 #s is the semi perimeter
area= math.sqrt(s*(s-a)*(s-b)*(s-c))
return area
print(calculateArea (4, 6, 8))
```

**Line 1**: Function definition to calculate the area of a triangle using given sides i.e.**a**,**b**, and**c**.**Line 2**: Calculating the semi perimeter of the triangle by calculating the sum of sides & dividing it by 2.**Line 3**: Computing the area by calculating the square root of the product of`s(s-a)(s-b)(s-c)`

.**Line 4**: Returning the area computed by`calculateArea()`

.**Line 6**: Invoking`calculateArea()`

method with**4**,**6**, and**8**values for**a**,**b**, and**c**respectively to calculate the area of a triangle.