To be considered safe for ocean sailing, the capsize screening value C should be less than 2 For a boat with a beam (or width) b in feet and displacement d in pounds, C is determined by the function C=4d^-1/3b.

a) Find the capsize screening value for the Tartan 4100 which has a displacement of 23,245 lbs and a beam of 13.5 ft.

( I know how to set up the problem but not how to solve it I have an example of how to solve but I do not understand how they got the first part of the answer .. If I find out how I can solve it )) ANY help is greatly appreciated ! :)

Question

To be considered safe for ocean sailing, the capsize screening value C should be less than 2  For a boat with a beam (or width) b in feet and displacement d in pounds, C is determined by the function C=4d^-1/3b.

a) Find the capsize screening value for the Tartan 4100 which has a displacement of 23,245 lbs and a beam of 13.5 ft. 

( I know how to set up the problem but not how to solve it I have an example of how to solve but I do not understand how they got the first part of the answer .. If I find out how I can solve it )) ANY help is greatly appreciated ! :)