A triangle has sides with lengths: 6, 1, and 5. How do you find the area of the triangle using Heron's formula?

1 Answer
Jan 25, 2016

First, find the semiperimeter #s=(1/2)(6+1+5)=6#. Now, use Heron's area formula ...

Explanation:

Heron's Area #=sqrt(s(s-a)(s-b)(s-c))#

Area #=sqrt(6(6-6)(6-1)(6-5))=0#

Why is the area 0?

The Triangle Inequality Theorem states that the length of any side of a triangle MUST be less than the sum of the other two sides. For this problem, the theorem fails the test :

#6# is not less than #1+5#

So, a triangle with sides 6, 1 and 5 is not a triangle!

hope that helped