Answer:2.91666666667
Step-by-step explanation:
The answer I believe is the third choice.
3, -2, -7, -12
These all fit into f(n)-5=f(n+1)
Sorry if this is messy but I hope it helps you
Perimeter of triangle = 3(side)
P = 3(s)
12 = 3s
12/3 = s
4 = s
I think there is a typo in your post.
The question should be: WHICH ONE OF THE FOLLOWING IS A POSSIBLE SIDE OF THE TRIANGLE?
In that case, 4 cm is the answer. However, 4 cm is not listed among the choices. So, choice d is the answer.
= 
= 7/4