Dimensions of room = 300m by 200m
Area of room = (300 * 200)m² = 60000m²
dimensions of carpet = 180m by 180m
Area of carpet = (180 * 180)m² = 32400m²
Area of not carpeted floor = area of floor - area of carpet
= (60000 - 32400)m²
= 27600m²