A building has an entry the shape of a parabolic arch 84 ft high and 42 ft wide at the base as shown below. Find an equation for the parabola if the vertex is put at the origin of the coordinate system.

Question

anonymous · Answer

attachment

anonymous · Answer

@Mertsj

mertsj · Answer

We see that (42,-84) is a point on the parabola.  We know the vertex is at the origin so the parabola is of the form y = ax^2.

mertsj · Answer

Replace y with -84 and x with 42 and calculate a.  Then you will have your equation.

anonymous · Answer

I got a really strange number for a

a= -0.0476190476

anonymous · Answer

@Mertsj

mertsj · Answer

Oh, sorry,  the point on the parabola is (21,-84)  The 42 is all the way across.

mertsj · Answer

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