# How do you write an inequality that expresses the reason the lengths 5 feet, 10 feet, and 20 feet could not be used to make a triangle?

##### 1 Answer
Nov 21, 2016

Let the lengths of the triangle be $a , b \mathmr{and} c$ with $a < b < c$.

Since a triangle is a closed three sided figure,

a + b ≥ c

Here, we let $a = 5$, $b = 10$ and $c = 20$.

5 + 10 ≥^? 20

15 ≥^O/ 20

So, it is impossible to have a triangle with sides of $5 , 10 \mathmr{and} 20$ feet.

Hopefully this helps!