# How do you use Heron's formula to find the area of a triangle with sides of lengths 5 , 4 , and 8 ?

##### 1 Answer
Mar 20, 2016

≈ 8.18 square units

#### Explanation:

This is a 2 step process

step 1 : Calculate half of the perimeter (s) of the triangle

let a = 5 , b = 4 and c = 8

$s = \frac{a + b + c}{2} = \frac{5 + 4 + 8}{2} = \frac{17}{2} = 8.5$

step 2 : Calculate the area using

area $= \sqrt{s \left(s - a\right) \left(s - b\right) \left(s - c\right)}$

$= \sqrt{8.5 \left(8.5 - 5\right) \left(8.5 - 4\right) \left(8.5 - 8\right)}$

 = sqrt(8.5xx3.5xx4.5xx0.5) ≈ 8.18" square units "