SOLUTION: A building has an entry the shape of a parabolic arch 96 ft high and 18 ft wide at the base. Find an equation for the parabola if the vertex is put at the origin of the coordinate

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: A building has an entry the shape of a parabolic arch 96 ft high and 18 ft wide at the base. Find an equation for the parabola if the vertex is put at the origin of the coordinate      Log On


   



Question 1094384: A building has an entry the shape of a parabolic arch 96 ft high and 18 ft wide at the base.
Find an equation for the parabola if the vertex is put at the origin of the coordinate system.
Please show all work because I'm super confused. Thank you so much! :)

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
A building has an entry the shape of a parabolic arch 96 ft high and 18 ft wide at the base.
Find an equation for the parabola if the vertex is put at the origin of the coordinate system.
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That gives 3 points:
(0,0), (-9,-96) and (9,-96)
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Since the vertex is (0,0):
y = -a*x^2
--> -96 = a*81
a = -96/81 = -32/27
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y+=+-32x%5E2%2F27 is the parabola