Question

Which set of three numbers could be the side lengths of a triangle?

А. 3, 5, 7
В. 2, 4, 8
с. 2, 4, 6
D. 3, 5, 9

Answer 1

А. 3, 5, 7

Explanation:

Because

7 - 3 = 4

7 + 3 = 10

then

7 - 3 < 5 < 7 + 3

the 3 other cases don’t fit with this rule.