<PRE><B>Question 1187061</B>
A parabolic arch has a span of 80 feet and a maximum height of 78 feet. Choose a suitable rectangular coordinate system and find the equation of the parabola.
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Parabolas have the form {{{ax^2 + bx + c = 0}}}
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Make the y-axis thru the vertex.
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Then you have 3 points:
(-40,0), (0,78) and (40,0)
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Can you do the rest?
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