Question 1086406
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The equation of this parabola is 

p(x) = {{{-(1/3)*(x-6)*(x+6)}}}

(6 units to the left from the vertical centerline to one root and 6 units to the right to the other root;
 and the vertex is at 12 ft up).


Now, the question asks about p(4), and you can easy calculate it:

p(4) = {{{-(1/3)*(4-6)*(4+6)}}} = {{{(-1/3)*(-2)*10}}} =  {{{20/3}}} = {{{6}}}{{{2/3}}} ft.
</pre>

<U>Answer</U>.  &nbsp;&nbsp;Verical clearance of the parabola &nbsp;4 feet from the vertical centerline is  &nbsp;{{{6}}}{{{2/3}}} &nbsp;ft.
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