Answer:

= 4.17

Jake's strand represents 4 times David's strand.
Explanation:
* microscope measured the diameter jake strand was 0.005 cm in the diameter
* David strand was 0.0012 cm in diameter
To find the ratio , we will have to divide them
k=0.005cm and
d=0.0012cm
by dividing we get,

= 4.17

Therefore, Jake's strand represents 4 times David's strand.