# How do you use Heron's formula to determine the area of a triangle with sides of that are 28, 29, and 42 units in length?

Apr 5, 2016

≈ 404.51 square units

#### Explanation:

This is a 2 step process.

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

let a = 28 , b = 29 and c = 42

then s $= \frac{a + b + c}{2} = \frac{28 + 29 + 42}{2} = \frac{99}{2} = 49.5$

step 2 : Calculate the area (A) using

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

 = sqrt(49.5(49.5-28)(49.5-29(49.5-42))

 = sqrt(49.5xx21.5xx20.5xx7.5) ≈ 404.51" square units "