Question

Which of these groups of numbers could NOT be the side lengths of a triangle? A. 11,13,15 B. 5,7,8 C. 2,4,4 D. 1,3,5

Answer 1

Triangles have to satisfy the triangle inequality, which says the sum of any two sides is strictly greater than the third.

That fails for triangle D, because 1 + 3 < 5

Answer: D