5. The Triangle Inequality
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Use the Triangle Inequality Theorem.
B
We are given the lengths of two of the triangle's sides, 5 yards and 9 yards. We will use the Triangle Inequality Theorem to figure out which of the given options is the least possible measurement of the third side. Let's find the sums of the side lengths to see if they meet the requirements for the Triangle Inequality Theorem.
| Option | Side Lengths | Sums |
|---|---|---|
| A | 4, 5, and 9 yards | 4 + 5 & = 9 & * 4 + 9 & > 5 & ✓ 5 + 9 & > 4 & ✓ |
| B | 5, 5, and 9 yards | 5 + 5 & > 9 & ✓ 5 + 9 & > 5 & ✓ 5 + 9 & > 5 & ✓ |
| C | 6, 5, and 9 yards | 6 + 5 & > 9 & ✓ 6 + 9 & > 5 & ✓ 5 + 9 & > 6 & ✓ |
| D | 14, 5, and 9 yards | 14 + 5 & > 9 & ✓ 14 + 9 & > 5 & ✓ 5 + 9 & = 14 & * |
Both 5 yards and 6 yards would satisfy the theorem but 5 is the lesser number so B is the correct answer.