Question

Which of the following can be the side lengths of a triangle?

A:12,9,21
B:7,6,12
C:3,8,14
D:23,13,37

Answer 1

In a triangle the sum of two sides is always greater than the third side.

A:12,9,21
12+9 = 21
21 = 21 ⇒ no

B:7,6,12
7+6 = 13
13 > 12 ⇒ yes

C:3,8,14
3+8 = 11
11 < 14 ⇒ no

D:23,13,37
23+13= 36
36 < 37 ⇒ no

Answer: B:7,6,12