# How do you use Heron's formula to find the area of a triangle with sides of lengths #23 #, #21 #, and #20 #?

##### 1 Answer

Feb 10, 2016

Find the semiperimeter first then use Heron's formula

Area is

#### Explanation:

Heron's formula states that

Area =

Where s is the sum of all sides / 2 (Also known as the semiperimeter)

a,b,c are the side lengths

From here, you can just plug in all the values.

Find that s = 32

Area =

prime factorize the inside to get

Then take out the squares to get

Finally