Math CentralQuandaries & Queries


I am trying to figure out how to work this problem as it doesn't have many details.

The problem ask for an equation to satisfy a parabolic arch y = 16 - 0.25x^2 for y>=0.

Find the width w of the arch.


You can find the width of the arch if you can find the x values where the parabola crosses the horizontal axis.

What is the value of y at both of these points? It is zero. So we can replace y with 0 in your equation:

0 = 16 - 0.25x2

Now if you solve for x, you will get two values of x which correspond to the two locations on the graph. What is the distance between these points? That's the width w.

Hope this helps,
Stephen La Rocque.

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