Question

Which of the following sets of possible side lengths does not form a triangle

a) 5,6,10
b) 4,5,15
c) 22,21,42
d) 3,4,5

Answer 1

b) 4,5,15

Explanation:

In a triangle of sides‘s length a , b and c

in order to be able to form (construct) this triangle we must have :

c - a < b < c + a

in fact this work with cases a) ,c) and d)

but not b)

because 15 - 4 is not < to 5

in other words 15 - 4 > 5