Answer:
(d) 10 cm, 15 cm, 23 cm
Step-by-step explanation:
21 cm, 7 cm, 11 cm — 7+11 < 21 . . . not a triangle
7 cm, 23 cm, 11 cm — 7+11 < 23 . . . not a triangle
12 cm, 7 cm, 19 cm — 7+12 = 19 . . . not a triangle
10 cm, 15 cm, 23 cm — 10+15 > 23 . . . can form a triangle
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The sum of the two shortest sides must exceed the length of the longest.
