We notice that the common ratio of teh sequence is 10, and that the first term is -0.56, then the recursive formula is:
Answer:
The total length of the two cables is 
Step-by-step explanation:
see the attached figure to better understand the problem
we know that
In the right triangle ABD
Applying the Pythagoras Theorem

substitute the given values



Remember that
AB=AC ----> because ABC is an isosceles triangle
so
The total length of the two cables is equal to

2 / 1386
3 / 693
3 / 231
7 / 77
11/ 11
/ 1
Prime factors = 2*3*3*7*11
Option C.