6. Inequalities in One Triangle
Sign In
Use the Triangle Inequality Theorem.
No, see solution.
We will check whether these sides can form a triangle. In order to do that, we will use the Triangle Inequality Theorem. This theorem tells us that the sum of the lengths of any two sides of a triangle is greater than the length of the third side.
Applying this theorem to the given side lengths, we have three inequalities. I:& 4+5? > 9 ⇒ 9 ≯ 9 II:& 5+ 9? > 4 ⇒ 14 > 4 III:& 9+ 4? >5 ⇒ 13 > 5 Since Inequality I is not true, a triangle cannot have these sides.