Question 336003
"Using an algebraic method, determine the equation of the catenary that you believe best models your necklace". Baiscally I had to make earlier a parabola by tracing a chain and then find an equation to match that parabola which i had difficulty with. Now later on, on a much harder question it was required for the parabola to be shitfed upwards on the y-axis and the equation to be calculated. 
I have obtained three coordinates that I tried to use but to no avail, they are 
Turning Point (0, 10) and (30,27) and (54,79). If a negative x-vaule would make it easier then those three a coordinate that could also be used is- (-54, 79). Any help would be greatly appreciated. I was attempting to use the formula y=ax^2+bx+c, as this formula is what is needed to be solved, that a-value, b-value and c-value.
---------
Using:::::: ax^2 + bx + c = y
(0,10):::::  0   +  0 + c = 10
(30,27):::: a*30^2+b*30+c = 27
(54,79):::: a*54^2+b*45+c = 79
---------------------------------
Using Matrix:
0::::0::::1::::10
30^2:30:::1::::27
54^2:54:::1::::79
-------------------------
a = 0.0296
b = -0.3222
c = 10
------------------------
Note: By the way, a catenary is not a parabola.
A catenary has its own equation form.  Check
Google to see more about catenaries.
==========================================
Cheers,
Stan H.