Question 239045
60 inches = 112 pounds
66 inches = 136 pounds


let x = inches and y = pounds


(x1,y1) = 60,112)
(x2,y2) = 66,136)


slope of straight line = y2-y1/(x2-x1) = (136-112)/(66-60) = 24/6 = 4


slope-intercept form of straight line equation is y = mx+b where m is the slope and b is the y-intercept.


your equation is y = 4x + b because it has a slope of 4.


substitute either one of the points (x1,y1) or (x2,y2) in the equation to solve for the y-intercept which is b.


equation of y = 4x + b becomes:


112 = 4*60 + b if we use (x1,y1).


solving for b we get:


112 = 240 + b
b = 112-240 = -128


equation becomes y = 4x - 128


graph of this equation looks like:


{{{graph(600,600,-10,100,-10,200,4x-128,112,136)}}}


the graph has y = 112 and 136 to show you that they occur at x = 60 and x = 66 as they should.


lso not very accurate although not quite as bad as on the low end.


If you restricted the domain for the value of x being from 50 to 70 then the graph straight line project might be ok.


Since this graph is a straight line calculated between only 2 points, it doesn't accurately portray the height to weight ratio at the extremes of the height range.