Can someone help me here and check out the other two i have posted there both due soon and i have no clue how to do them

Since the question doesn't mention in what tide the answer should be, I will be giving a solution to both, the high and low tide. Hope this helps :)

Step-by-step explanation:

Using a cosine function, where time is measured in hours past high

tide:  y=4cos30x + 10

Using a cosine function, where time is measured in hours past low

tide:  y = 4cos[30(x-6)]+10

18

step-by-step explanation:

draw the shape and you will see that f and k are actually at adjacent vertices (points of the hexagon that are neighboring).   so find the distance between (1,2) and (4,2).   that is easy since (1,2) and (4,2) is just a vertical distance to count, which is 3.   it is a regular polygon which means all sides are congruent.   you have 6 sides (hexa) so multiply 6 by 3 to receive 18.