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

Step-by-step 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

the surface area is 124cm²

step-by-step explanation:

length: 4cm

width: 9cm

height:   2cm