Chapter 8.3, Problem 2WE

To determine

To state: state whether the given sides are the sides of acute angle triangle, right angles or obtuse angle.

Answer to Problem 2WE

The given sides of triangle are the sides of obtuse angle triangle.

Explanation of Solution

Given information: We have the given the sides of triangle are $9,9,13$

Let ABC be a triangle.

Also let $a=9,b=9andc=13$

We see that

  $\begin{array}{c}{c}^2>a^2+b^2\\ {\left(13\right)}^2>{\left(9\right)}^2+{\left(9\right)}^2\\ 169>81+81\\ 169>162\end{array}$

Therefore from the converse of Pythagoras theorem if $c^2>a^2+b^2$ then $\Delta ABC$ is obtuse triangle.