To determine which set of side lengths does not form a triangle, we can use the triangle inequality theorem. According to this theorem, for any three sides (a, b, and c), the following conditions must be satisfied:
- a + b > c
- a + c > b
- b + c > a
Let's evaluate each set of side lengths:
-
9, 17, 11:
- 9 + 17 > 11 (26 > 11) ✅
- 9 + 11 > 17 (20 > 17) ✅
- 17 + 11 > 9 (28 > 9) ✅
- This set forms a triangle.
-
11, 19, 9:
- 11 + 19 > 9 (30 > 9) ✅
- 11 + 9 > 19 (20 > 19) ✅
- 19 + 9 > 11 (28 > 11) ✅
- This set forms a triangle.
-
18, 10, 8:
- 18 + 10 > 8 (28 > 8) ✅
- 18 + 8 > 10 (26 > 10) ✅
- 10 + 8 > 18 (18 > 18) ❌
- This set does not form a triangle.
-
18, 11, 8:
- 18 + 11 > 8 (29 > 8) ✅
- 18 + 8 > 11 (26 > 11) ✅
- 11 + 8 > 18 (19 > 18) ✅
- This set forms a triangle.
Thus, the set of side lengths that does not form a triangle is 18, 10, 8.