Assuming the length is y and the width is x Perimeter = y + y + x + x = 2y +2x = 2 (y + x) if the is 8 and the perimeter is 108 108 = 2 (y +8) 108/2 = y+8 54 = y +8 54 - 8 = y 46 = y
The domain of the function is \[A \ge0\] If A is negative we get an imaginary number for the radius. This makes sense because the area of a circle cannot be negative.
