Can you help me please?

Question

1. 

Answer 1

In a triangle the sum of the lengths of any two sides is greater than the length of the 3rd side.

a) 16, 9, 8

sum of 16 and 9 = 25 > 8

sum of 16 and 8 = 24 > 9

sum of 8 and 8 = 17 > 16

this is a triangle

b) 28, 15, 12

sum of 15 and 12 = 27 < 28

not a triangle

c) 40, 26, 13

sum of 26 and 13 = 39 < 40

not a triangle

d) 3, 2, 1

sum of 2 and 1 = 3 = 3

not a triangle

only a) is a triangle