Ok i’m stuck again sadly, college online won’t show the example right that i’m stuck on to and the book doesn’t show how to do this one, #8

A∪B = include all the possible elements in A and in B.

A∪B = (-∞ , ∞ )

6.3

To solve this, we are going to use the Pythagorean inequality, which states that for an obtuse triangle or shorter sides and and longest side ,  .

We know from our problem that the shorter sides of our triangle are x cm and 3x cm, so and ; we also know that its longest side is 20 cm, so . Let's replace the values in our Pythagorean inequality an solve for :

And rounded to the nearest tenth:

The greatest possible value of x is 6.3 cm