Answer:
From the level of high tide to low tide, it's 18 feet.
Step-by-step explanation:
To find the change in water level, we multiply the rate (3 ft / hr) by the time (6 hrs), obtaining 18 ft.
The water level changes by 18 ft.
59.6 is the answer rounded to the nearest tenth
Divide the numerator of the fraction by the denominator. the first two digits of the decimal is the percentage
I’m not sure, you’re not elaborating enough to this equation. Are you sure you’re not missing a phrase of some sort?
Answer:

Step-by-step explanation:
To solve this problem you must know the formula of subtraction of angles for the function cosx.
The formula is:

We can write 30° as: 45° - 15°
Then:

Using the formula for subtraction of angles we have:

Notice that we have achieved the expression shown in the statement
Finally:
