Final answer:
Frank Lloyd Wright's concept of 'Broadacre City' focused on decentralization, individualism, and harmony with nature. His Usonian house designs supported these principles through open floor plans, integration with nature, and affordability for the middle class.
Step-by-step explanation:
Frank Lloyd Wright's concept of 'Broadacre City' had three main principles: decentralization, individualism, and harmony with nature. Wright believed in spreading out cities into the countryside to give each person their own plot of land and create a more balanced distribution of resources. His Usonian house designs fit into this concept by emphasizing open floor plans, integration with nature, and affordability for the middle class.