Which three lengths could be the lengths of the sides of a triangle?

13 cm, 5 cm, 18 cm

21 cm, 7 cm, 7 cm

8 cm, 23 cm, 11 cm

9 cm, 15 cm, 22 cm

To solve this problem, one needs to know the Triangle Inequality property. The Triangle Inequality property states that the length of two legs of a triangle will always be greater than the third leg. That being said, the only one that works is D., the one with legs 9 cm, 15 cm, and 22 cm.