CPM Homework Help : CCA2 Problem 7-124

David Longshot is known for his long golf drives. Today he hit the ball $250$ yards and estimated that the ball reached a maximum height of $15$ yards. Find a quadratic equation that would model the path of the golf ball.

Hint:

A sketch of the graph would look like the one below.

First quadrant, x axis scaled in 50's, from 0 to 300, Curve, opening down, rises through the origin, to the point (125, comma 15), then falls & passes through the point (250, comma 0).

More Help:

You must find the value of a for the quadratic equation.
$y = a\left(x − h\right)^{2} + k$
What is the vertex?
Use the vertex and another point to solve for $a$ .

Answer:

$a=-\frac{3}{3125}=-0.00096\ \\ y=-\frac{3}{3125}\left(x-125\right)^2+15$