Question 1155249
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Let the origin be center of the base of the arch.  The vertex of the parabola is then at (0,35); and two points on the parabola are (-76,0) and (76,0).<br>
The equation of the parabola is of the form<br>
{{{y = 35-ax^2}}}<br>
where the value of the coefficient a is determined by the point (76,0) on the parabola.<br>
{{{0 = 35-a(76^2)}}}
{{{a(76^2) = 35}}}
{{{x = 35/76^2}}}<br>
So the equation of the parabola is<br>
{{{y = 35-(35/76^2)x^2}}}<br>
{{{graph(800,200,-80,80,-10,40,35-(35/76^2)x^2)}}}<br>
To find the height of the arch 25 feet from its center, simply find the value of y when x is 25.<br>
I leave that much of the problem for you....<br>