Question

Sarah throws rocks into a quarry lake from the top of a 67 foot high wall. The chart gives the horizontal distance, x (in feet), the rock has travled from Sarah and the height, y (in feet), of the rock above the lake.

The chart is:
|distance, x:|9| 19| 36|50|
|height, y: |75.39|81.10|82.07|74.61|

I think the answer is possibly y=-0.019x^2+1.10x+67, but I am not sure. Could someone help me please?

Answer 1

well, you are correct that we have a parabola here of form a x^2 + b x + c
since you just asked me to check your answer and not to show you how to do it I will cheat and just check.
first make sure some point in the middle satisfies your equation
82.07 = -.01(36)^2 +1.1(36)+67 ????
93.64, well not too bad because your coefficients seem to be rounded to two places
try first point
75.39 = -.01(9)^2 + 1.1(9) + 67 ???
78.09 not bad
check the other two points but I think you did it right but without carrying enough significant figures in your solution of the simultaneous equations.

Answer 2

Okay, I wasn't sure if my answer was right, so thank you!