Isolved most of the problem already, but i need with the last part.
part 1
you will need to measure five different people. record your measurements on a piece of paper. using a tape measure or ruler, measure the length (in inches) of a person’s left foot and then measure the length (in inches) of that same person’s forearm (between their wrist and elbow). refer to the diagrams below. you will have two measurements for each person.
(an easy way to measure the length of a foot is to have your subject stand on a piece of paper. then, trace their foot and measure the outline once they move off the paper.)
to measure the forearm, measure inside the arm, between the wrist and the elbow.
part 2
organize your data and find the rate of change.
a. a. create a table of the measurements for your data. label the forearm measurements as your input and the foot measurements as your output.
b. measurement of people's left foot (in inches):
c. 30, 34, 35, 38, 40
d.
e. measurement of people's forearm (in inches):
f. 14, 17, 18, 21, 23
g.
h. b. select two sets of points and find the rate of change for your data.
i. my two points = (30, 14) and (34, 17)
j. rate of change, m = y2-y1/x2-x1
k. m = 17 - 14 / 34 - 30
l. m = 3 / 4
m. c. describe your results. if you had to express this relation as a verbal statement, how would you describe it?
n.
o.
p. c) in order to form an equation, take any point, let say (14, 30)
q. y - y1 = m(x - x1)
r. y - 30 = 3/4 (x - 14)
s. y - 30 = 3x/4 - 10.5
t. y = 3x/4 + 19.5
where, y = length of left foot
x = length of forearm
when x = 17 ft, it would be:  
y = 3(17) / 4 + 19.5
y = 12.75 + 19.5
y = 32.25 ft
part 3
compare rates of change.
a. the equation below can be used to find the length of a foot or forearm when you know one or the other.


(length of the foot) = 0.860 • (length of the forearm) + 3.302 


if you let y = length of the foot and x = length of the forearm, this equation can be simplified to y = 0.860x + 3.302.
using this equation, how long would the foot of a person be if his forearm was 17 inches long?
y=length of foot
x= length of your forearm. 
the equation is y=0.860x + 3.302
so, if you have a forearm (x) that is 17 inches long, then plug in x as 17. this leaves you to evaluate for y.
new equation: y=0.860(17) +3.302
work it out, you get: y=14.62 + 3.302
work that out, you get: y= 17.922 inches long. 
and, y is the foot.
so, if the forearm is 17 inches long, then the foot is 17.922 inches long.
a. b. what is the rate of change of the equation from part a? rate of change. well, you need slope then, because that's the same thing.
b. y=mx+b, where m=slope
c. the answer is 0.860 inches per length of arm, for rate of change.

d. d.
compare the equation from part a to your data. are they the same? which has a greater rate of change? why do you think the values are different?
part a
the
a. c. is the relation in your data a function? why or why not? could the equation in part a represent a function? why or why not? explain your answer.
b. there can't be any exponents greater than 1 on the placeholder, and it's obviously not a straight line if you plug it in.
c.