# How do you use Heron's formula to find the area of a triangle with sides of lengths #9 #, #5 #, and #12 #?

##### 1 Answer

Jan 21, 2016

Use Heron's formula to find area

#### Explanation:

Heron's formula gives the area

#A = sqrt(s(s-a)(s-b)(s-c))#

In our example,

#A = sqrt(s(s-a)(s-b)(s-c))#

#= sqrt(13*4*8*1) = sqrt(416) = 4sqrt(26) ~~ 20.396#