The maximum area is the area that uses half the fence (150 ft) for the side parallel to the barn and the other half for the ends of the pen (75 ft each). That area is 11,250 ft^2.
Since 0.10 is a decimal, multiplying 104.3 by 0.10 is actually dividing 104.3 by 10. Thus 104.3 multiplied by 0.10 is 10.43
