From the table, 5 houses sold.
The total price is
548,000 + 480,200 + 650,500 +,488,000 +,578,000 = $2,744,700
The total area is
3200 + 3100 + 3350 + 3225 + 2800 = 15,675 ft²
The price per square feet is
2744700/15675 = $175.1005 per sq. ft.
Marty's house 2950 ft².
On the basis of area, Marty's house should sell for
(2950 ft²)*(175.1005 $/ft²) = $516,546.41 = $516,500 (nearest hundredth)
Answer: $516,500 (nearest hundredth)