Answer:

Step-by-step explanation:
The function that could model this periodic phenomenon will be of the form

The tide varies between 3ft and 9ft, which means its amplitude
is

and its midline
is
.
Furthermore, since at
the tide is at its lowest ( 3 feet ), we know that the trigonometric function we must use is
.
The period of the full cycle is 14 hours, which means


giving us

With all of the values of the variables in place, the function modeling the situation now becomes

There are 31+42+50+61=184 total females, and 50+61=111 females in grades 11 and 12, so the percentage is 111/184*100=60.33 percent, which can be rounded to 60%.
First set the equation equal to y by adding x to each side, then divide everything by 8. then set x to zero and solve to find the y - intercept of 1/2 which is just 4/8 reduced. you get this answer because x/8 becoming 0/8 is just 0 leaving you with only 1/2. then reset the equation with x and set y to zero and solve for x to get the x- intercept of -4. you get this by subtracting 1/2 from both sides leaving you -1/2=x/8 and multiply by 8 to get -4=x