Answer:
42.25 feet
Step-by-step explanation:
The maximum of a quadratic can be found by finding the vertex of the parabola that the quadratic creates visually on a graph.
So first step to find the maximum height is to find the x-coordinate of the vertex.
After you find the x-coordinate of the vertex, you will want to find the y that corresponds by using the given equation,
. The y-coordinate we will get will be the maximum height.
Let's start.
The x-coordinate of the vertex is
.
compare to
.
We have that
.
Let's plug into
with those values.
with 
.
The vertex's x-coordinate is 13/8.
Now to find the corresponding y-coordinate.

I'm going to just put this in the calculator:

So the maximum is 42.25 feet.