McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
5. The Triangle Inequality
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Exercise 11 Page 449

Yes, see solution.

Practice makes perfect

We have been given the following potential side lengths. 1 15 km 4 12 km 3 34 km 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.

XY+YZ>XZ YZ+XZ>XY XZ+XY>YZ Applying this theorem to the given side lengths, we have three inequalities. I:&1 15+4 12? >3 34 ⇒ 5 710 > 3 34 II:&4 12+3 34? >1 15 ⇒ 8 14 > 1 15 III:&3 34+1 15? >4 12 ⇒ 4 1920 > 4 12 Since all three inequalities are true, a triangle can have these side lengths.