1748 m²
================
First, find the area of the lot, assuming it is rectangle:
- A(lot) = 50 m * 40 m = 2000 m²
Find the area of the house, again assuming it is rectangle:
- A(house) = 28 m * 9 m = 252 m²
Find the difference of areas:
So 1748 m² of area is left over.