To find the maximum area of the dog run, we can analyze the given equation for area, which is:
\[ A = -w^2 + 60w \]
This is a quadratic equation in the standard form \( A = ax^2 + bx + c \), where \( a = -1 \), \( b = 60 \), and \( c = 0 \).
The maximum value of a quadratic equation in this form occurs at the vertex, which can be found using the formula:
\[ w = -\frac{b}{2a} \]
Substituting in the values for \( a \) and \( b \):
\[ w = -\frac{60}{2(-1)} = \frac{60}{2} = 30 \]
Now that we have the width \( w = 30 \) feet, we can find the corresponding area by substituting this value back into the area equation:
\[ A = -30^2 + 60(30) \] \[ A = -900 + 1800 \] \[ A = 900 \]
Thus, the maximum area of the fence that can be created is:
900 square feet.